ALBERT

Notes: SYNOPSIS. Ten new species of colorless Eugleninae are described. One of them is the type of a new genus (Calycimonas physaloides nov. gen. nov. sp.). Especially remarkable forms are: Astasia acus, a species related to the green Euglena acus but without chromatophores and stigma and considerably smaller; Astasia edax, a species with animal-like nutrition and peculiar ecological adaptations; Petalomonas striata, a form which is not spirally but transversely striated; and finally Hyalophacus caecus, which was observed already by Klebs and Pochmann but was not sufficiently described. The new genus Calycimonas (ex fam. Peranemacearum) is related to Tropidoscyphus on the one hand (nearly the same shape as e.g. Tr. octocostatus, but possessing only a single flagellum) and to Petalomonas on the other hand (mode of nutrition and of swimming, formation of the reservoir, rigidity: however in transverse section not flattened).The Astasiae with zootrophic nutrition are collected in a new subgenus Astasiae devorantes or Phytophaga which comprises besides A. edax three species already described by Skuja.

Notes: SYNOPSIS. H. canis (James) is reported from three of 36 stray dogs at Singapore and one of 34 palm civets (Paradoxurus hermaphroditus Pallas) from Jeram, Selangor. H. muris (Balfour) was found at Singapore in 10 of 61 examples of Rattus norvegicus (Erxleben) and five of 23 of R. rattus diardi (Jentinck), and is also recorded from six of 139 examples of R. r. jarak (Bonhote) from Pulau Jarak, Straits of Malacca. Neutrophils of P. hermaphroditus containing gametocytes of H. canis exhibit pronounced karyorrhexis, while most of the parasites themselves show signs of pyknosis.

Notes: SYNOPSIS. A total of 155 clones of Stylonychia putrina collected in nature were tested for mating type. Two sexually isolated varieties were found among them: Variety I with 12 mating types and Var. II with 11. Five of the clones isolated in the laboratory belonged to 3 additional mating types of Var. I making a total of 15 mating types in this variety.Crosses were made among 6 of the mating types of Var. I, and 114 clones of progeny were raised and tested for mating type. No simple genetic explanation of the results was evident.An abnormal type of conjugation with fusion of the conjugants and subsequent fission was studied. Both parental mating types sometimes segregated during the first two fissions of a fused animal. Mating type determination in the progeny of the fused animals seemed to parallel that of the progeny of the normal conjugants in that in both cases certain mating types tended to be dominant over others.

Notes: SYNOPSIS. The cytochemical procedure of Sen was used to demonstrate urease activity in Tetrahymena pyriformis S.

Notes: SYNOPSIS. The chimpanzee is shown to behave like man to infection with Babesia divergens or bovis: the intact animal is totally resistant, whereas the splenectomized animal develops a fulminating infection accompanied by blackwater. The splenectomized rhesus monkey reacts in the same way also, but splenectomized rabbits are insusceptible. In the chimpanzee the typical accolé position of the “divergens” organisms (as seen in cattle) is absent, but occurs in the rhesus. It is suggested that latent piroplasmosis in man may exist on a large scale in rural populations in infected localities.

Notes: SYNOPSIS. Studies cf 3 conjugating strains of Tetrahymena pyriformis grown in a bacterized medium indicated the presence of a system of alternative immobilizing surface antigens. Each strain was found to have the potential for the expression of 3 serologically unrelated antigens. These consisted of a “high temperature” antigen (expressed in the range of 20–35d̀C), a “low temperature” antigen (exhibited in cultures at 10d̀), and an antigen induced by growth in the presence of the above-mentioned “high temperature” antiserum. Normally, by the immobilization reaction, only one of these antigens could be detected as present on any one organism at any given time. The “high temperature” antigens of two of the strains were serclogically related while that of the 3rd strain did not cross-react with antisera to the other two. The “low temperature” antigens of the 3 strains were serologically related as were the antigens induced by growth in antiserum.Studies of inbred hybrids of two of the strains indicated a potential for still more alternative antigens as well as for the spontaneous expression of the antigen which in the parental strains could only be induced to appear by the presence of the specific antiserum.Study of the 3 strains in axenic medium indicated the existence of a more complex system and the possibility that two or more immobilizing antigens may be present simultaneously.

Notes: SYNOPSIS. The establishment of Eimeria tenella sporozoites in the cecal mucosa of the chicken is described. The invasion process was similar to that reported for E. necatrix by Van Doorninck and Becker. Sporozoites were found to pass through the surface epithelium of the cecal mucosa into the lamina propria. Within the lamina propria the sporozoites were engulfed by macrophages and transported to the cells of the glands of Lieberkühn. Development of the sporozoites ensues within the gland epithelium.

Notes: SYNOPSIS. The morphology of the vegetative phase and the sexual process in Pandorina morum have been studied in detail under controlled laboratory conditions. A number of strains from various areas of the United States, all essentially indistinguishable on morphological grounds, were analyzed for sexual compatibility. Forty-seven heterothallic clones were found to represent 15 separate pairs of mating types, or a minimum of 15 syngens (sensu Sonneborn, 1957). Two clones proved to be homothallic. Nine additional clones, which were not observed to mate with any strain, can be classified only after further collecting. The separate heterothallic pairs of mating types are sexually isolated by factors acting at the stage of gamete production; incompatible mating types produce no gametes when they are mixed together. The geographical distribution of the sets of mating types is very incompletely defined as yet, but they are not strictly endemic forms. Thirty heterothallic strains, representing each of the 15 sexually isolated sets of mating types of Pandorina morum, have been deposited with the Culture Collection of Algae maintained at Indiana University, Bloomington, Indiana, U.S.A.

Notes: SYNOPSIS. When grown in CPLM medium or in a similar medium containing glucose instead of maltose as its sugar, Tritrichomonas foetus, Strain O, was much more sensitive to injury when frozen to -21d̀ C. in the presence. of 1 m glycerol during the initial and logarithmic phases of its population growth curve than at its peak and for some time thereafter. In 7 experiments in which the population peak occurred an average of 28.1 hours after inoculation, the average culture age at which the protozoa first survived freezing was 20.3 hours, at which time the population had reached 52.6% of its peak. The optimum culture age for survival after 1 day of freezing averaged 37.7 hours at which time the population averaged 75.6% of its peak. The optimum culture age for survival after 7 to 15 days of freezing averaged 32.3 hours, at which time the population averaged 82.7% of its peak. Better survival upon freezing was obtained in those experiments in which the population peak was reached relatively rapidly.

Notes: SYNOPSIS. Specimens of Blepharisma undulans were transferred from young clone cultures to a rotocompressor with 3 mm3 of culture medium. The organisms were slightly compressed and photographed at various intervals with dark field illumination. The sequence of macronuclear and cytoplasmic changes was compared with similarly followed Feulgen preparations.The cycle falls into several phases: (1) an interphase (12–24 hr.) in which the organism increases in size while cytoplasmic and macronuclear appearances remain unchanged. During this phase, the macronucleus consists of 3 to 5 nodes of various sizes connected by strands. (2) a pre-condensation phase (1 hr.) in which a new posterior peristome and cytopyge appear without visible macronuclear change. (3) a condensation phase (10–20 min.) in which the macronuclear nodes coalesce into a round mass without dissolution of the central nodes or strands. (4) a postcondensation phase (1 hr.) characterized by: (a) elongation of the condensed macronucleus into a rod-like shape followed by typical nodal formation; or (b) elongation of the condensed macronucleus into a form resembling the letter “J”, followed by nodal formation, and resulting in a double row of nodes in one daughter and a single row in the other. Separation occurs at this time, initiating the new interphase. The development of the j-form macronucleus. the lack of obliteration of the central nodes, and the characteristic interphase condition distinguish this strain of B. undulans from others described elsewhere.

Notes: SYNOPSIS. Six species of astomatous Infusoria, 4 new, are described from the alimentary tract of Oligochaeta from Ochrida Lake. Two belong to Ochridanus, characterized by a cytoskeleton whose “V”-shaped basal piece bears on its branches two articulated hooks brought together by a skeletal blade. This genus found in Ochridanous Tubificidae represents the counterpart of Anthonyella in the Lumbriculidae of Lake Baïkal. The presence of Ochridanus in these worms concurs with the almost complete absence of representatives of Radiophrya of which we have found but one species. A species of Metaradiophrya, a genus unknown to date from the Lumbricidae, was noticed in Glossoscolecidae. The different species of Ochridanus, Anthonyella, Metaradiophrya, and Radiophrya compose a very homogeneous group of Radiophryinae. The study of the ciliary rows and the cytoskeleton of 2 species of Juxtaradiophrya, parasitic in the Lumbriculidae of Ochrida, shows that, in the morphology of these ciliates, as well as in the same forms from Lake Baïkal, many transition characteristics exist between the Radiophryinae and Hoplitophryinae or Mesnilellinae. These 3 sub-families, with their undeniable genetic kinship give coherence to the family Hoplitophryidae.

Notes: SYNOPSIS. Histochemical techniques were used to demonstrate the intracellular distribution of some hydrases, hydrolases, oxidases, and dehydrogenases in Stylonychia pustulata. The hydrase, aconitase, was confined to the mitochondria. Zymohexase activity occurred in the cytoplasm and probably in the mitochondria. The hydrolases, acid and alkaline phosphatases, lipase, and urease, were localized in the mitochondria. Lactic and glutamic dehydrogenases were confined to the mitochondria. Peroxidase and glycerophosphate dehydrogenase were absent.

Notes: SYNOPSIS. When two strains cf T. pyriformis that do not require exogenous pyridoxine are crossed, all progeny grow without the vitamin. Offspring from crosses of two pyridoxine requiring clones require pyridoxine with the exception of a few which will grow without pyridoxine. The ratio is approximately 3:1 favoring the pyridoxine requiring category. In matings involving the homozygous dominant pyridoxine requiring clones with the double recessive mutant, that is +/+ X p/p, all of the resulting progeny need pyridoxine. Test crossing these heterozygotes (+/p) with the parental pyridoxine non-requiring clones (p/p) gives offspring approximating a 1:1 ratio. Matings between two heterozygotes derived from breeding experiments also yield progeny in approximately 3 pyridoxine requiring: 1 pyridoxine non-requiring. All data indicate selection for the heterozygote in the population and a possible selection against either homozygote. The great abundance of heterozygotes and rarity of recessive homozygotes in natural habitats corroborates these findings. The genetic evidence supports a single gene hypothesis although the possibility of multiple closely linked genes cannot be ignored. There is also the possibility that a dominant suppressor gene may function in blocking the activity of the pyridoxine mutant genes. Moreover, if this gene exists it may be incompletely dominant since the heterozygote grows slightly on deficient media.

Notes: SYNOPSIS. Trichodina urinicola was found in newts, Triturus cristatus and T. taeniatus, in three localities in Czechoslovakia. The ciliate populations showed important differences on the basis of which they were separated as three new forms of this species: T. urinicola f. typica, T. urinicola f. bohemica, both from Triturus cristatus, and T. urinicola f. taeniatus from Triturus taeniatus. The great variability of trichodinids is evident from the literature as well as from our own observations, so that these new forms are to be regarded as provisional ones until it is possible to decide on the basis of a large number of observations the extent of specificity and variation of individual endozoic species of Trichodina. A detailed description of these forms is given as well as a comparison with the known species of trichodinids inhabiting the urinary tract of amphibians. A brief comment on the present taxonomy of the Urceolaridae in general is outlined.The need for a uniform description of these ciliates is emphasized; in connection with this, the taxonomic value of individual body characters is discussed. Special attention is paid to the adhesive disk of Trichodina, the structure of which is of greatest importance in the taxonomy of this group. On the basis of Dogel's and Fauré-Fremiet's descriptive methods employed in study of trichodinids, a proposal of a uniform description of Trichodina is made which involves all the important features of these protozoa.

Notes: SYNOPSIS. Several substrains of Euglena gracilis var. bacillaris made chlorotic by treatment with pyribenzamine or streptomycin, or by growth at high temperature (35–36°C.), have been examined for their carotenoid content. They differ from the normal green strain both qualitatively and quantitatively. Some strains produce no detectable carotenoids while the carotenoid concentration in the strains producing most is at best only one-fifth that of the normal strain. In all substrains producing carotenoids, the carotene fraction consists of β-carotene accompanied by some members of the phytofluene series. In only two of these substrains, HB-G and PBZ-G3, are xanthophylls produced in significant amounts. In HB-G, the main pigment is echinenone, and in PBZ-G3 it is zeaxanthin. The significance of these findings is briefly discussed.

Notes: SYNOPSIS. Association of gamonts of Pyxinia crystalligera takes place in the midgut of its beetle host, Dermestes vulpinus. At 25°C. the development of gametocysts to the point of liberation of sporocysts is completed between about 15 hours and 27 hours after the gametocysts are deposited with fecal material. Dehiscence is favored by relative humidities of 0% to 90%, but is not favored by a relative humidity of 100%. During the early development of the gametocysts outside the host, the crystals and paraglycogen granules in the cytoplasm of the associated gamonts become concentrated in large masses. The gametes are formed at the periphery of the gamonts. After fusion of the gametes takes place and the sporoblasts begin to develop, the residual cytoplasm containing the inclusions moves outward to form a continuous layer next to the gametocyst envelope, so that the sporoblasts become crowded into a central core. A few hours before dehiscence is initiated a clear area appears on the upper side of the gametocyst. The contents of the gametocyst begin to shrink away from the envelope except in the region of the clear area. Eventually the sporocysts emerge through the clear area and press against the envelope of the gametocyst, causing formation of a conical papilla in the envelope. With continued pressure from the sporocysts, the papilla ruptures at its tip, and the sporocysts emerge in a continuous thread until dehiscence is completed. The thread of sporocysts may attain a length of about 11 mm.

Notes: SYNOPSIS. The steps leading to purine ring closure were examined in Strigomonas oncopelti. The flagellate has an obligate adenine requirement (hypoxanthine and guanine are inert) when grown without p-aminobenzoic acid. The imidazole counterpart of adenine but not the imidazole counterpart of hypoxanthine was active. A pathway for purine biosynthesis compatible with these results is sketched.

Notes: SYNOPSIS. The Nuttallia of the gerbil is transmitted by Rhipicephalus secundus only if the infected meal is taken by the larva, and the subsequent nymphal stage is the only one which is able to infect. There is no transovarial transmission.Infective trophozoites remain in the larval caeca for about 12 hours after gorging. The infective nymph is able to give rise to new infections at various times after it has been allowed to feed, but never later than the third day after disengagement from the host.

Notes: SYNOPSIS. The process of autogamy in unassociated individuals of Paramecium polycaryum was reported by the author in 1954. In May, 1955, conjugation was first seen in this species in cultures collected by me at Annamalainagar, South India, thus removing it from the list of non-conjugating species. This appears to be the first instance in which the process of autogamy was detected prior to observation of conjugation in the same species. Autogamy occurs in singles of the Indian race and appears to be similar, cytologically, to that of American races. The details of the micronuclear behavior in conjugation parallel those of autogamy in singles. In fact, the conjugation process seems to be one of double autogamy (cytogamy), rather than of reciprocal gametic interchange. Paroral cones, often of fair size, are formed but breakdown of the cones to permit micronuclear passage has not been observed. In conjugation there are the usual three pregamic divisions; the first shows four characteristic crescents. The resulting nuclei may all participate in the second division. Fertilization occurs in the paroral cone area. Frequently, separation of the conjugants takes place immediately after the first division of the synkaryon. The old macronucleus undergoes very little change prior to the last postzygotic micronuclear division in the ex-conjugant, when it goes into a skein condition. Four macronuclear and four micronuclear anlagen are formed in the ex-conjugants at the completion of reorganization. On occasion giant individuals of P. polycaryum were observed to have ingested numbers of Tetrahymena pyriformis. The presence of an unidentified rod-like organism in the cytoplasm of the paramecia (non-conjugating) was detected in one collection from Bangalore, India.

Notes: SYNOPSIS. The oocysts, sporulation process, and endogenous stages of Eimeria raillieti (Léger, 1899) Galli-Valerio, 1930 from the slow-worm, Anguis fragilis, in England are described. The oocysts average 18 × 15 μ. Schizonts, microgametocytes and macrogametocytes were found in the ileum, and macro-gametocytes alone in the duodenum.

Notes: SYNOPSIS. Zooxanthellae in pure culture, exposed to continuous light, release free O2 in amounts varying with time and cell number. Zooxanthellae exposed to alternate light and dark produce essentially as much O2 as in continuous light. Those in continuous dark do not yield free O2; rather, they draw from the medium's residual O2.Both the anemone Condylactis and the scyphozoan Cassiopeia are markedly phototactic. Kept in total darkness, both species show a dramatic numerical diminution in zooxanthellae. During 24 days of darkness, the mean total number of zooxanthellae in the individual Condylactis body was reduced from 26 million to ∼ 1 million. Specimens so bleached lost phototaxis.It is suggested that each species of zooxanthella host animal has its own specific light needs, which it caters to in various ways: (a) early selection of position, as with planulae or other freely motile larval forms; (b) gross body movement or posturing, as with anemones, medusae, and worms; (c) possession of light-filtering pigments, as with colored corals and molluscs; (d) possession of light-concentrating devices, as with tridacnids; (e) possession of highly contractile and differentially light-absorbing tissues, as with most coelenterates and some molluscs.Susceptibility of marine invertebrates to zooxanthellae infection may be related to the known paucity of nitrates and phosphates in tropical seas, a situation possibly inducing the free-swimming gymnodinioid forms to enter animal tissues where catabolic products are available to them. Zooxanthellae are reported from sessile marine invertebrates taken at depths of 100–116 fathoms.

Notes: SYNOPSIS. All of 99 adult English house-sparrows, examined in the St. Albans area of Hertfordshire, England, were found to be infected with the organism previously defined by Garnham (1950) as Atoxoplasma. Young birds were found to become infected while still in the nests and as early as 6 days after hatching; there was no evidence to suggest that the parasite was transmitted through the egg. Within a few weeks of leaving the nests, all of 150 fledgling sparrows examined were heavily infected and several trapped birds died from massive infections.All stages of schizogony were found in the lymphoid-macrophage cells of the spleen, bone marrow and liver of these birds; later, as the schizogonic cycle abated, gametocytes developed in similar cells of the liver, lungs and kidney. These gametocytes are of the Eimeria type: the zygote nucleus divides to produce an asporous and polyzoic oocyst containing a large number of sporozoites, and after the rupture of the oocyst these sporozoites invade the lymphocytes and monocytes of the peripheral blood.Transmission of the parasite in the sparrow is thought to take place after the ingestion of infected mites (Dermanyssus gallinae) by the young birds in the nests: unchanged sporozoites were found in smears of these mites that had been fed on infected sparrows. Transmission experiments were impossible due to the complete lack of clean sparrows.The taxonomic status of Atoxoplasma is discussed. The type of life cycle and the production of asporous, polyzoic oocysts indicate inclusion of this parasite in the Order Coccidiida, Family Eimeriidae, Sub-Family Cryptosporidiinae Hoare, 1933. After comparison of the two genera, the author concludes that Atoxoplasma must be regarded as a synonym for Lankesterella. Some previously described species of Atoxoplasma are, therefore, transferred to the genus Lankesterella.The name Lankesterella garnhami nov. sp., is proposed for the parasite in the English sparrow (Passer domesticus domesticus), and Lankesterella serini nov. sp., for that in the canary (Serinus canarius).

Notes: SYNOPSIS. Darkness and O2-lack promote formation of a pheophytin-like pigment from chlorophyll in Euglena gracilis in an acidic medium. Dinitrophenol (DNP) produces similar but more drastic pigment alterations in aerated and illuminated cells. The extent of pigment decay was dependent on DNP concentration and external pH. Since volume expansion and inhibition of the contractile vacuole were also noted, it is suggested that pheophytin formation is secondary to hydrogen ion influx from the external medium. Major structural alterations of the chloroplast accompanied the pigment changes.Pentachlorophenol, iodoacetamide, Na fluoride, and Na azide produced similar pigment changes. Malonic acid and fluoroacetate were ineffective under the conditions described. However, in the dark, cells treated with fluoroacetate formed pheophytin rapidly. These effects are discussed in relation to the maintenance of intracellular [H+].

Notes: SYNOPSIS. The heterotrophic, phototrophic, and phagotrophic nutrition of the chrysomonad flagellates Ochromonas malhamensis and O. danica were compared. Unlike O. malhamensis, O. danica, which is much richer in chloroplast pigments, grew readily photoautotrophically in a substrate-free medium in 5% CO2. Utilization of bound biotin in bacterial (Thiobacillus) bodies served to demonstrate phagotrophy in both flagellates. This nutritional versatility suggests that this group of flagellates will be exceptionally valuable for studying the evolutionary steps connecting photoautotrophy, heterotrophy, and phagotrophy.

Notes: SYNOPSIS. In a synthetic medium containing 57 compounds, including cholesterol, Trichomonas gallinae and T. gallinarum require 3 factors for growth and acid fermentation of maltose: (1) factor R, found in the protein contaminating some samples of ribonucleic acid, and in other isolated proteins such as conalbumin, γ-globulin, and bovine albumin fraction V; (2) factor T, found in Trypticase and in the same isolated proteins, but with activity at 4 times the dose required for factor-R activity, may be a large peptide containing proline; (3) factor S, found in serum, was replaceable by a saturated and an unsaturated fatty acid, each inactive alone. Only C14 through C18 saturated fatty acids were active over a range of 0.058 to 2.34 μm per tube in the presence of oleic acid, while C18 through C22 unsaturated fatty acids were active in the same range with palmitic acid as the supplement. The unsaturated fatty acids were toxic at the largest dose. All fatty acids were not equally active. Surface-active agents containing mixtures of fatty acids also replaced serum. A 4th factor, found in serum, stimulates the rate of growth as shown by cell counts at 3 days of incubation. T. gallinarum, T. foetus, and a trichomonad from a pig's nose responded to the same supplements when grown on another synthetic medium.

Notes: SYNOPSIS. Differences in temperature-tolerance, generation time, nutritional requirements, osmoresistance, pigment production, and sensitivity to high hydrogen or hydroxyl ion concentration have been observed among varieties, and among mating types within varieties of Tetrahymena pyriformis. The usefulness of these differences to taxonomists and geneticists is discussed.The nutrition of a temperature-tolerant strain, mating type II, variety 1, was given special attention and a chemicallydefined medium devised to support rapid growth at 35d̀ C. At 40d̀, growth in this medium failed, but was good in a crude medium. Temperature factors are suggested. Permeability of this ciliate, as inferred by utilization of nucleotides, was high.

Notes: SYNOPSIS. Eight strains of Tetrahymena pyriformis were examined in multiple daily isolation series over ∼ 800 generations. Dead and defective lineages appeared in all clones. In 7, the defective sub-lines appeared at a constant characteristic rate; the 8th showed an increasing rate of production of two defects. A breeding analysis of certain persistent morphological and growth rate variants suggests that the variations derive from macronuclear alterations. The relationship between these cellular changes and “senility” in metazoa and other protozoa is discussed.

Notes: SYNOPSIS. An acetone-insoluble yeast fraction required for axenic growth of P. aurelia, stock 51, variety 4, sensitive, after fractionation contained at least 3 essential components: (1) one soluble in perchloric acid and completely replaceable by a mixture of ribosides or ribotides; (2) one inactivated after digestion with trypsin, chymotrypsin or papain. Proteose-Peptone restored activity to this preparation, which suggests a peptide requirement; and (3) one not yet characterized.As for the purine and pyrimidines, these combinations, in decreasing order of activity, supported growth: guanosine + cytidine, guanosine + uridine, guanylic acid + cytidylic acid, and guanylic acid + uridylic acid. Each combination was maximally effective when the molar purine: pyrimidine ratio was ∼ 0.4. On a molar basis, the minimal riboside combinations were ∼ 1.3 × more active than the ribotides.Sparing of the purine and pyrimidine requirement was also investigated. In the presence of limiting amounts of guanylic acid, the following compounds, in decreasing order of activity, had sparing activity: deoxyguanosine, inosine, xanthosine, adenylic acid, and guanine. Adenine, adenosine, and deoxyadenosine were inhibitory under the test conditions. The requirement for cytidylic acid was spared by deoxycytidine, uridine, uridylic acid, deoxyuridine, thymidine, thymine, and uracil, in descending order.

Notes: SYNOPSIS. In reviewing 25 years of work on Tetrahymena, the author describes early difficulties experienced by himself and others in developing a chemically-defined medium and in defining the taxonomy of T. pyriformis. With identification of its essential requirements, a variety of nutritional studies revealed the close resemblance between the metabolic pathways of this ciliate and those of the chick and rat. This suggested studies on the effects of gamma radiation and the effect of antibiotics.Attention then turned to the puzzle of the absence of conjugation in all strains of T. pyriformis then maintained in laboratories. The observation that these strains were all amicronucleate led to the discovery of mating types (with D. F. Gruchy). This brought up the problem of what constitutes a species and how it might be solved in T. pyriformis where clearly defined groups are set off from other similar groups (varieties) by a breeding barrier.Another problem is whether a life cycle exists in this ciliate and if so, the role amicronucleate strains play in this cycle.The origin and obvious evolutionary success of these “genetically dead” strains are other problems that are considered.The search for nutritional markers for genetic experiments inspired large-scale collections, including some from tropical habitats. Strains were found which differed in serine and pyridoxine requirements. Genetic analysis was hindered by the high lethality following conjugation, unsatisfactory mating behavior in some clones, and the complete absence of autogamy, the latter making it difficult to obtain homozygous clones. The use of x-radiation yielded haploid individuals; when these were mated with diploid clones the resulting haploid progeny proved that the genes controlling mating type and pyridoxine synthesis resided in the micronucleus.Genetic analysis of the serine and pyridoxine mutants supports the idea that T. pyriformis is more of an outbreeder than an inbreeder. Left for the future is an extension of our knowledge of the breeding system of T. pyriformis and ultimately to examine critically the factors responsible for the success of this ubiquitous ciliate.

Notes: SYNOPSIS. The effects of some environmental influences on the cycle of Trypanosoma diemyctyli in Triturus v. viridescens are described. Bleeding of the host produced a reduction in the number of trypanosomes but did not affect their growth rate. The temperature at which the host was maintained affected the cycle of the trypanosomes. The length of the post-inoculation latent stage increased from 24 hours at 25°C. to an indefinitely long time at 5°C. The trypanosomes were found to be dimorphic. Adult parasites of the short form had a range of 45–75 μ and those of the long form of 76–116 μ. Growth rate of the trypanosomes was inhibited or greatly retarded at temperatures of 10°C. or lower and was greatest at 25°C. The size attained by the parasites and the number of parasites were greatest at 15°C. At this temperature the infection was pathogenic and the dimorphic parasites were in their long form. At the higher temperatures (20–25°C.) the infection was non-pathogenic with the trypanosomes in their short form.The infection is primarily one of adult newts. Experiments indicated that the larvae were resistant to the trypanosomes at all temperatures while the red efts were not. The latter are usually free from the trypanosomes because they are not exposed to them. Attempts to infect other newts and to locate any cryptic stages by the injection of blood and tissues from infected newts gave negative results.Starvation, sodium salicylate, and treatments used to control fungus infection of the newts had no detectable effects on the trypanosomes.

Notes: SYNOPSIS. A comparative study of five species of Tetrahymena, including thirteen strains, was made to ascertain their ability to act as facultative parasites. A variety of experimental hosts, including both vertebrates and invertebrates, were inoculated with axenic cultures of protozoa. Infections were numerous in both larval and adult insects. Tissues of living vertebrates were invaded by one species of Tetrahymena through artificially produced wounds.

Notes: SYNOPSIS. Unabsorbed, complement-inactivated antisera produced in rabbits were used in an immobilization system to study the serology of 31 strains of Tetrahymena pyriformis grown in axenic cultures at 26°C. Fourteen serological “groups” were found: 1. “H”: H, E, S, GC, L3, W, T, GHH, G1-R and sublines W-P and T-P; 2. “PR”: PR; 3. “GL”: GL; 4. “LR”: LR; 5. “L1”: L1 and L2; 6. “GP”: GP and Ch-S; 7. “WH”: WH6, WH14 and WH52; 8. “N”: N and HS; 9. “Y”: Y and TC; 10. “AA”: AA1, AA2 and AA4; 11. “F”: F and BF; 12. “Gf-J”: Gf-J; 13. “EZ”: EZ; 14. “Lava”: Lava. Not all of these “groups” were completely distinct; weak or variable cross-reactions occurring for particular cultures and antisera during the course of several years of observation suggested a relationship in terms of serotype potentialities, for strains in groups 1 and 2, and in groups 2, 3, 4, 5, and 6. Non-reciprocal cross-reactions are tentatively explained in terms of population fluctuations of serotype within particular cultures; several other suggested explanations remain possible. On the whole, however, the strains remained remarkably stable in dominant serotype.Observations on Tetrahymena in paralyzing antisera, with respect to the extrusion of a gelatinous exudate, in general confirmed previous observations by others. “Chain” formation was noted upon recovery, under conditions suggesting that the chains do not always derive entirely from incomplete cytokinesis of dividing organisms but that at least sometimes an aggregation of separate individuals is also involved. Synchronized division was observed for recovering organisms. A gelatinous material was obtained by centrifugation of a large number of individuals; this material provided a degree of protection to the organisms against antiserum effects while other colloidal materials did not, but the protective effects proved nonspecific in the sense that they were not confined to particular strain-antiserum combinations.

Notes: SYNOPSIS. During encystment of Colpoda cucullus (O. F. Müller) the respiratory rate decreases from about 11.3 × 10-5μl. O2/hr. (mean value for active form) to about 1.3 × 10-5μl./hr. (mean for unstable cyst); the process takes about 24 hrs. At the same time the activity of the contractile vacuole is stopped, but there is no correlation in time between the two processes: when respiration is inhibited by 1/2–2/3 the vacuolar activity is hardly changed. The respiration of unstable cysts remains approximately constant at least for 4 weeks. Experiments with methylene blue suggest that inhibition of respiration at encystment may be due to inhibition of terminal oxidase.

Notes: SYNOPSIS. Two isolates (“A” and “B”) of Trypanosoma lewisi from the same rat stock source were serially transferred in calorically-restricted mice supplemented daily with normal rat serum. The “A” strain was transferred consecutively through 300 mice over a period of more than 3 years and was voluntarily discontinued. The “B” strain died out spontaneously after 43 consecutive passages in mice. The developmental histories of these 2 isolates were analyzed and compared with respect to duration of the parasitemic period, interval to the next subsequent passage in mice, day of death of each host animal, proportion of host animals that died, intensity of parasitemia in mouse tail blood, interval required for development of the observed maximal parasitemia, and duration of maximal parasitemia.“A” appeared to have become progressively adapted to the mouse as judged by a decrease in parasitemic period with successive transfer associated with a progressive increase in trypanosome population, and declines in the interval required for development of the observed maximal parasitemia and in the duration of this maximal response. There did not appear to be any correlation of the percentage of animals that died with any other factor. The “B” strain did not appear to have adapted itself to mice as judged by the foregoing criteria.

Notes: SYNOPSIS. The Indian race of Blepharisma undulans described in this paper measures 150 μ in length. The macronucleus consists of 5–7 nodes, all of equal size. During binary fission, condensation of macronucleus is followed by its elongation and a thinning of the middle region which breaks with the division of the animal. It later attains the typical vegetative form.During conjugation 7 or 8 micronuclei pass through the first pregamic division, 5 to 7 through the second pregamic division and one product of the second division takes part in the third division. The rest degenerate. At the same time, the macronucleus also starts degenerating. After the synkaryon has divided twice, the conjugating pairs separate. Of the 4 products, 3 become macronuclear anlagen and one, micronuclear anlage.The micronuclei divide asynchronously both during binary fission and during conjugation. There is apparently considerable diversity in the structure and behaviour of the macronucleus and micronuclei in the different races of Blepharisma undulans.

Notes: SYNOPSIS. In cattle fed a high-starch diet, species of Entodinium and Diplodinium ingested associated ruminal bacteria. Stained preparations of diluted rumen contents showed Entodinium caudatum, E. minimum, E. dubardi, (syn. E. simplex), E. longinucleatum, E. bursa, E. nanellum, E. exiguum, and E. vorax contained gram-positive diplococci. Starch grains with adherent gram-positive diplococci were observed within Entodinium spp. Diplodinium ecaudatum forma ecaudatum, D. ecaudatum forma caudatum, D. neglectum and an unidentified species of Diplodinium also ingested ruminal diplococci. Bacteria were isolated from mixed species of Entodinium by washing and culturing the protozoa in a starch feed-extract agar medium. The strains isolated from the ciliates were gram-positive diplococci, 0.8 times 1–1.5 μm, which attached themselves to starch granules and were able to digest the starch. Conclusive evidence of bacterial ingestion by the oligotrichs was obtained by providing the bacterial cultures to Entodinium species (E. dubardi and E. minimum) which had been starved 24 hr. Gram-stained preparations showed the ciliates readily ingested the bacteria. The amylolytic cocci utilized by Entodinium spp. were identified as Streptococcus bovis.

Notes: SYNOPSIS. Lankesterella corvi n. sp. (Coccidia, Eimeriidae, Cryptosporidiinae) is described from the rook, Corvus f. frugilegus L. in England. It was found in 36 of 196 fledged rooks less than 1-year old, but not in 25 nestlings or 38 adults. It was not found in 71 jackdaws (C. monedula spermologus) or in 110 other birds of 16 species.Mature sporozoites were found in the erythrocytes and occasionally in other blood cells. They were 6.2 times 2.5 μ, with a central, band-like nucleus, and cytoplasm which failed to stain with Giemsa's stain. Gametogonic and sporogonic stages, found in the bone-marrow of one bird, resembled corresponding stages of Eimeria.A fledgling rook was infected experimentally by inoculation of a blood and tissue suspension from an infected bird. Sporozoites appeared in its blood 4 days after inoculation. They appeared to increase slightly in size and their cytoplasm lost its initial affinity for Giemsa's stain during the next few days. Engorged mites (Ornithonyssus sylviarum) from the experimentally infected rock contained unchanged sporozoites but no developmental stages of the parasite. A canary could not be infected by intraperitoneal inoculation and feeding of such mites.

Notes: SYNOPSIS. A dichotomous, analytical key is offered for use in recognition and differentiation of the 26 orders and suborders belonging to the two subclasses of the single class Ciliata of the subphylum CILIOPHORA. The basic terminology employed in these brief characterizations, usable in systematic studies of ciliates in general, is defined first, and a plea is made for a more uniform vocabulary, especially in reference to structures which are without doubt homologous throughout the several higher ciliate taxa. Particular emphasis is placed on the all-important features in the oral area; many of these are figured as well as being described in words.Both the key and the definitions are essentially the first to be offered since Kahl's monographic work on the ciliates published in 1930–1935. They are demanded by the great accumulation of new pertinent data in the protozoclogical literature of the past 25 years.

Notes: SYNOPSIS. The flagellate, Peranema trichophorum, has been studied in the electron microscope by thin-sectioning techniques. The flagella have the fibrillar pattern typical of cilia and flagella, but accessory structures including tapered, intraflagellar rods, striated, layered material on the outside of the membrane, and mastigonemes are present. In the near basal region of the flagellum, there is a swelling of the shaft which is correlated with the absence of the two central flagellar fibrils. The basal portion of the intraflagellar material is structurally and locationally similar to the basal parts of the flagellar fibril bundle; this similarity suggests that the two structures originated from similar precursors and that two kinetosomes comprise the light microscopist's blepharoplast in this organism.The ridged pellicle is composed of 3 membranes, only two of which follow the contour of the ridges. Several filaments 21 mμ in diameter are localized under the low point of each ridge, and a single, larger fibril which has a periodic structure is often located beneath the high point of each ridge.The cytostome and structures associated with it are described and discussed in relation to food taking. The pharyngeal rods are cross-connected and each is composed of numerous tubular elements surrounded by a denser, homogeneous layer. A system of membranes is attached to the rods and extends anteriorly.The nucleus contains two large nucleoli, numerous rod-shaped, membrane-limited bodies which appear similar in structure to bacteria, and a smaller granular component.Other organelles are briefly described including mitochondria, Golgi bodies, vacuoles, and endoplasmic reticulum.

Notes: SYNOPSIS. Materials within the endoplasm of both the protomerite and deutomerite may be displaced and stratified by ultracentrifugation. Animals are not killed by this treatment, and in time a redistribution of stratified materials may occur. The electron microscope reveals numerous ultramicroscopic folds in the surface envelope which is composed of 3 membranes; the outer and middle cover the surface of the folds while the inner one continues as a smooth membrane over the ectoplasm. The contact surfaces of animals in syzygy do not show the small folds to be interlocked; instead, they are in fold-to-fold contact. Numerous relatively dense bodies which appear to be filamentous are sometimes observed immediately underneath or within the middle or inner membrane. Within the ectoplasm is an ultramicroscopic net-like fibrillar structure much denser than the surrounding cytoplasm. This system of fibrils is composed of anastomosing elements varying from ∼ 50 to 200 Å in diameter. Certain of the larger fibrils are directly attached to the surface envelope at positions between the folds. A second filamentous structure within the ectoplasm appears to be tubular. Elements of this system also appear to join and penetrate the surface envelope by means of pores.A large amount of gelatinous secretion forms at the surface of the sporont; as it glides forward a trail of mucous is left behind. The actual mechanism involved in the gliding movement was unobserved, but evidence is lacking to support the view that the gliding movement is engendered by posteriorly directed “jets” of mucus.

Notes: SYNOPSIS. Vorticellas were subjected to achromycin, polymyxin, and mixtures of penicillin-streptomycin to remove bacterial contaminants. Although achromycin and polymyxin were most effective in controlling bacteria isolated from vorticella cultures, they proved too toxic for practical use. However, certain dilutions of penicillin-streptomycin were tolerated by vorticellas and, therefore, were incorporated into the axenizing procedure. Yeasts did not yield to the antibiotics and had to be removed by washing and dilution. Sterile vorticellas were finally obtained by transfer of groups of individuals through 6 washes. One of these, the 4th, lasted 8 hours and contained diluted penicillin-streptomycin.

Notes: SYNOPSIS. The interphase nucleus of Lesquereusia spiralis, a testate rhizopod, 20–25 μ in diameter, contains 40–50 endosomes and a diffuse granular reticulum. Onset of nuclear division is marked by a cessation of pseudopod activity. Prophase changes include increase in size of the nucleus, disappearance of the endosomes except the peripheral ones, formation of 175–200 chromosomes from the reticulum, and the appearance of spindle fibers. By the end of prophase a well formed equatorial plate is present. The metaphase nucleus is slightly smaller and elongated; the chromosomes remain distinct. In anaphase the nucleus continues to elongate along the polar axis; the chromosomes apparently split lengthwise and polar caps appear. The nucleus elongates further so that by telophase it has become hour-glass shaped. The spindle fibers are now twisted. Separation of the nuclei takes place in the neck region. The nuclear membrane is unbroken during the process and peripheral endosomes are present at all stages. Total time for mitosis averages 45 minutes.

Notes: SYNOPSIS. Three gregarines are described from the digestive tracts of marine crustacea from Bombay, India. These are Carcinoecetes etisi n.sp. from Etisus laevimanus, C. matutae n.sp. from Matuta lunaris, and Caridohabitans setnai n.gen., n.sp. from Peneus semisulcatus. Various life history stages are reported.

Notes: SYNOPSIS. In various ciliates the contractile vacuole is a permanent organelle, delimited by a differentiated cortex.The cortex is made up of a dense reticulum of anastomosing tubules limited by a smooth membrane, and vesicles. This “spongiome” can be considered as a localized and specialized condensation of the endoplasmic reticulum.

Notes: SYNOPSIS. Two species of flagellate parasites, Herpetomonas muscarum (Leidy 1856) Kent 1881 and Crithidia luciliae (Strickland 1911) have been isolated in pure culture from the fly, Phaenicia sericata. Laboratory-reared Musca domestica were infected with each of the species. These two species have often been confused, the latter being regarded as “cysts” of the former. H. muscarum is long and slender and occurs actively swimming in the midgut of the host. C. luciliae is short and truncate and occurs mainly in the hindgut where it is often attached to the gut wall. C. luciliae grows readily and abundantly in culture and outgrows H. muscarum in mixed cultures. Attempts to infect Aedes aegypti and Culex pipiens with C. luciliae failed while control feedings of these mosquitoes with Crithidia fasciculata produced infections.

Notes: SYNOPSIS. Trimastigamoeba philippinensis Whitmore 1911 from Florida was cultured in the laboratory at 22 to 25° C. on a modified Bunting's agar medium overlaid or not with Neff's ameba-saline. Studies of its general morphology, transition from ameboid to flagellate phase and vice versa, encystment, and excystment were made. In general, Whitmore's observations are confirmed, except for his conclusions concerning the number of flagella and whether or not there is a rhizoplast. The flagellate phase has two mastigonts, each composed of a pair of flagella attached to a basal granule (blepharoplast). Intermediate stages in the development of the mastigonts may have caused Whitmore to decide that a tri-flagellar phase was the usual condition. The two mastigonts are not at any time attached to one another, nor to the nucleus, nor is there any evidence of a rhizoplast or rhizostyle. In the flagellate phase the bases of the mastigonts are closely surrounded by an anterior, gullet-like invagination, posterior to which the blepharoplasts rest adjacent to the nucleus. The four flagella extend 20 to 25 μ beyond the anterior limit of the pocket. Detailed descriptions of the morphologies of the ameboid and flagellate phases are given to supplement the morphology described by Whitmore. Possible affinities to other amebo-flagellates are discussed. It is concluded that the organism is generically and specifically distinct; and while its name is erroneously descriptive of its flagellate phase, it is taxonomically valid.

Notes: SYNOPSIS. The organism used in the experiments fits Pierson's satisfactory description for Euplotes eurystomus. The mating behavior of 90 stocks of E. eurystomus collected from west Japan was studied. Mating occurs only after a decline in nutritive conditions. When the stocks were mixed together, two at a time, in all possible combinations, mating took place in all the mixtures. Mating occurs in the evening or the morning after mixing. An agglutinative reaction does not precede mating; but before pair formation, characteristic pre-pairing behavior is observed. Selfing is found in all the stocks, usually after the log-phase of the growth curve. Culture fluids from various cultures have no detectable capacity to induce selfing, but some of them can suppress selfing. The latter occurs only in specific combinations. Controls mixed with distilled water instead of culture fluid always contain selfers. From the results of such experiments, it is possible to classify the stocks into 9 types, so that stocks of the same type have the same character with respect to suppression of selfing. The culture fluid from type II suppresses selfing only in animals of type I, type IV acts only on type III, VI on V, VIII on VII, and VII on both V and VI. The reciprocal actions also occur, i.e., fluid from I suppresses selfing of type II, etc. The origin of the two mating members of a conjugating pair was traced by making mixtures of normal animals of one type with morphologically abnormal animals of another type. The latter have a distinct swelling at the left margin of the body. Such mixtures (I × II, V × VI and VII × VIII) yield conjugating pairs of normal mated with abnormal animals, i.e. cross-conjugating pairs, in 86–94% of the animals. Mixtures of type VI with VII yield a smaller percentage (48%) of cross-conjugating pairs. Mixtures of two cultures belonging to the same type, (II × II, VI × VI and VIII × VIII), in which selfing is not suppressed, yield 42–50% conjugating pairs of normal with normal, (selfing of the normal culture), and 32–45% conjugating pairs of abnormal with abnormal, (selfing in the abnormal culture). Mixtures of two cultures belonging to diverse types in which selfing is not suppressed (I × V, I × VIII, II × III, II × VII, II × IX, III × V, III × VI, III × VIII, IV × VI and VI × IX), yield 36–48% conjugating pairs (selfing) of normal with normal, and 26–50% conjugating pairs (selfing) of abnormal with abnormal. Interbreeding between two types thus normally occurs only when culture fluid of each type inhibits selfing by animals of the other type. These two types, which interbreed freely, may be considered as complementary mating types. The mating types of E. eurystomus thus fall into 5 varieties so that each one (except the fifth) has two complementary mating types. The mating types are numbered I and II in variety 1, III and IV in variety 2, V and VI in variety 3, VII and VIII in variety 4, and only IX in variety 5. Intervarietal mating does not occur in many combinations, but exceptionally it occurs between types V and VII, and between VI and VII. These hybrids become senile and finally die.

Notes: SYNOPSIS. A rapid quantitative method for measuring trypanostatic activity by means of the nonpathogenic flagellate Herpetomonas culicidarum is described. Of the known trypanocidal agents tested, pentamidine was the most active; stilbamidine and propamidine somewhat less active. H. culicidarum is more resistant to these agents than are some pathogenic hemoflagellates. Two new antifungal antibiotics, nystatin and heptamycin (a candicidin-like antibiotic), had powerful trypanostatic activity in vitro. The potential trypanostatic activity of antifungal agents is noted.

Notes: SYNOPSIS. Approximately fifty % of Natrix piscator from the vicinity of Bombay showed a haemogregarine in the peripheral blood. Schizogonic stages were found in great abundance in the lung capillaries, and occasionally in other internal organs. No parasites could be demonstrated in trombiculid mites of the genus Schongastia fed on infected snakes. Various developmental stages were found in the leech, Hirudinaria granulosa allowed to feed on infected Natrix piscator. The haemogregarine was originally described from this host in Ceylon on the basis of blood stages only and was named Haemogregarina mirabilis. Although the parasite exhibits several of the characters diagnostic of the schizogonic stages of the genus Hepatozoon, it is advisable for the present to retain it in the genus Haemogregarina.

Notes: SYNOPSIS. A new species of a freshwater reticulate dinoflagellate, Woloszynskia limnetica, is described. The membrane structure and the shape of the membrane plates change during cell development. The rod-shaped mitochondria found among the membrane plates disappear in the adult cells; they constitute a center from which starch grains develop. Mitochondria also occur free in the endoplasm. Different physiological activities appear to be performed by morphologically identical chondriosomes. The stigma changes in different phases of the life cycle. The physicochemical properties of the ectoplasm govern the formation of specific structures of the membrane plates, which in turn determine the taxonomic position.

Notes: SYNOPSIS. Pseudomicrothorax dubius, a rather rare protozoon assigned by Kahl to the trichostome order of ciliates, has been found and positively identified for the first time in America, and its morphology and morphogenesis have been studied in detail with the aid of modern techniques. The Chatton-Lwoff silver impregnation method is considered indispensable in acquiring an understanding of the ciliate's infraciliature: both its anatomy in the mature vegetative animal and its activities during the morphogenetics of binary fission.Stomatogenesis is of a complex type, considered here as “semi-autonomous” in nature, although a single, true stomatogenous meridian also is involved. Details of this explicit morphogenetic phenomenon are offered.The presence of a true zone of three adoral membranelles, never before recognized with any accuracy in this ciliate, a buccal cavity and associated structures, and the mode of stomatogenesis have led the writers to propose transfer of the genus Pseudomicrothorax from the Trichostomatida to the order Hymenostomatida.

Notes: SYNOPSIS. Studies of the body ciliature of Balantidium coli and B. caviae (?) after Breslau's opal-blue and Klein's silver nitrate techniques revealed a preoral-dorsal suture area where some of the ciliary rows fail to reach the peristomial margin. The incomplete kineties ranged up to a dozen in number and were variable in arrangement. In a count of 100 specimens of B. caviae (?) the incomplete kineties were at the right of the suture in 39, at the left in 24 and on both sides of the suture line in 37. At the posterior end not many kineties reach the pole but no sutural pattern was seen in that region. Scattered irregularities in the ciliary rows were sometimes seen.Studies of the oral region tend to confirm the view of Fauré-Fremiet that the peristomial ciliature consists of short rows of cilia which are continuations of the anterior body kineties. Membranelles were not found. Thus, some species of Balantidium, at least, show affinities with the Holotricha in agreement with Nie and Fauré-Fremiet.Fission commonly produces two equal-sized daughters but many cases of unequal division were observed. In both these species conjugants are much smaller than vegetative animals and two preconjugant divisions are indicated, the first of which may be unequal.During the early stages of fission, the anterior ends of the kineties of the posterior daughter change direction, becoming oblique in the fission zone. In this region the kinetosomes multiply; possibly some of the kineties also divide but evidence for this is incomplete. No evidence of reorganization at the anterior end of the anterior daughter was seen.Attempts to infect hamsters with B. coli and B. caviae (?) failed. No parasites were found in two collared peccaries repeatedly examined.

Notes: SYNOPSIS. Purification by migration on solid agar plates was studied with a small soil amoeba, Acanthamoeba sp., and a large fresh-water amoeba, Amoeba proteus. Purification seems accomplished largely by two mechanisms: egestion and attrition of contaminating organisms. Digestion may also play a role but probably is less important. The migration method is applicable to motile forms of the two amoebae which differ greatly in volume and motility. Therefore the method may be of potential value in purifying many species. Modifications which should extend the usefulness of the method are considered.

Notes: SYNOPSIS. The gametes of Trichonympha grandis fuse quite differently from those of all the other species of Trichonympha in Cryptocercus; fusion is partial and temporary instead of complete and permanent as in other species. In this species, as in the others, fusion brings about the disintegration of all the extranuclear organelles of the male gamete, but none of those of the female; these persist to become the organelles of the zygote. Gametic union accomplishes two things: loss of extranuclear organelles of male and fusion of pronuclei. Unlike that of the other species of Trichonympha, the cytoplasm of the male gamete of T. grandis contributes slightly, if at all, to the formation of the zygote.

Notes: SYNOPSIS. A new species of Hepatocystis (H. hippopotami) is described from the blood and liver of a Rhodesian hippopotamus (Hippopotamus amphibius). Its relationship with other members of the genus is briefly discussed.

Notes: SYNOPSIS. The role of eleven different types of achromatic figures in chromosomal movement of Barbulanympha is analyzed. When only one pole is present, no chromosomes are ever connected with it, and hence they do not move. The chromosomes go through their usual life cycle including pairing, but remain in the parent nucleus, which, of course, does not divide. When two poles are present with only one pole near the nucleus, the poles, which are the distal ends of the elongate centrioles, do not cooperate in the formation of a central spindle and the chromosomal behavior is just as if there were only one pole—no movement. The same is true when more than two poles are present with only one near the nucleus.Unless a central spindle is present, movement of chromosomes never occurs. However, when many central spindles are present, sister chromosomes may separate and move to poles which are not directly connected by a central spindle. In other words, sisters may separate without moving along a central spindle.In binucleate cells with one central spindle the chromosomes of one nucleus move to the poles, but those of the other do not. Movement always occurs in the nucleus that has its nuclear membrane depressed by the central spindle. When two or more central spindles are present, the chromosomes of both nuclei may move to the poles.

Notes: SYNOPSIS. Euplotes eurystomus Wrzesniowski was cultured on bacterial media with Tetrahymena pyriformis serving as the food organism. Animals were injured with various types of operations using the Chambers' micromanipulator. These animals were followed during the course of their regeneration using various nuclear stains, silver impregnation techniques and vital staining methods. It was found that two cirral fields arose as a result of injury removing one or more of the locomotor organelles and that the posterior field was soon resorbed, while the anterior one replaced all of the old cirri of the regenerating animal. In addition, in response to this sort of injury, complete nuclear reorganization took place. Animals which were injured in a manner not affecting the locomotor organelles directly, responded by proliferating a fine network in the area of injury. This network seemed to reinforce the injured area and persisted until the next binary fission of the animal. No nuclear reorganization took place in these cases.

Notes: SYNOPSIS. The leech, Erpobdella sp., is a suitable invertebrate host for Trypanosoma ambystomae. The developmental cycle involves a mononucleate, rounded body derived from the bloodstream form; this body then transforms into a large plump crithidia. Subsequent divisions yield medium crithidia, small crithidia, and ultimately, metacyclic trypanosomes.

Notes: SYNOPSIS. Two methods for purifying balantidia are described. The first one may be applied to cultures which are not thriving when it is desirable to keep the purified ciliates without loss in number. Another method may be used for bulk material such as intestinal contents containing these ciliates.

Notes: SYNOPSIS. A piroplasm occurring in the erythrocytes of 38 of 42 echidnas (Tachyglossus aculeatus) has been described and named Babesia tachyglossi.

Notes: SYNOPSIS. Identical cultural forms of Trypanosoma granulosae occur in NNN agar, Diamonds SNB-9 agar and Proteosepeptone blood agar. The inclusion of penicillin G sulfate and streptomycin had no effect upon the cultures. The first cultural forms to appear (24 hours) were long, slender crithidia which divided to produce short slender crithidia. The latter were the only forms encountered until the 18th day when rosettes, composed of 3–10 short, slender crithidia were found. Following the production of metacyclic trypanosomes (24th day) the culture rapidly died. Transfer of metacyclic trypanosomes and rosettes did not extend the length of culture life. T. diemyctyli is also unaffected by antibiotics and shows similar growth in all media used. Division in this species begins 50–96 hours after inoculation with the production, from the blood stream form, of two unequal, plump crithidia. These divide twice to form slender crithidia; the latter rapidly divide, but do not separate, and yield rosettes with a maximum number of 60 individuals. As the slender crithidia leave the rosette each either remains in the same form or transforms to a plump, pear shaped individual. Secondary rosettes are then formed from the latter. Metacyclic trypanosomes appear, in small numbers, after the 14th day.

Notes: SYNOPSIS. In a survey of coccidia of rodents from Harbel, Libera, the following species of Eimeria were found and described: E. musculoidei n. sp. from Mus (Leggada) musculoides; E. separata Becker & Hall, 1931 from Rattus (Dephomys) defua (new host record); E. praomysis n. sp. from Rattus (Praomys) tullbergi rostratus; E. dasymysis n. sp. from Dasymys incomptus rufulus; E. lemniscomysis n. sp. from Lemniscomys striatus striatus; and E. lophuromysis n. sp., E. sikapusii n. sp., E. liberiensis n. sp., E. harbelensis n. sp., E. africana n. sp., and E. kruidenieri n. sp. from Lophuromys sikapusi sikapusi.

Notes: SYNOPSIS. The morphology of 4 genera of the family Trypanosomatidae has been studied with particular reference to the contractile vacuole, reservoir, flagellum, undulating membrane, kinetoplast, and nucleus. Both the contractile vacuole and reservoir have been found in all species examined. Four morphological types of culture forms are described with special reference to these structures: (1), the Crithidia fasciculata type which is short and membraneless with a rounded posterior end, truncate anterior end and a well developed reservoir; (2) the Herpetomonas muscarum type with no undulating membrane, a truncate posterior end, a rounded anterior end and a reservoir which varies in length from about 1/6 of the length of the body to the full length of the body; (3) the Leishmania type with no undulating membrane, a pointed posterior end, an asymmetrical anterior end and a short reservoir which remains constant in size; and (4), the short-membraned type exemplified by Trypanosoma cruzi, with a pointed posterior end, a short reservoir near the middle of the body and the flagellum attached to the body along a portion of its length. This last form is derived from the blood stream morphology as exemplified by Trypanosoma lewisi in the rat by a shifting of the kinetoplast, flagellum, reservoir and contractile vacuole along the surface of the body from a position posterior to a position anterior to the nucleus.

Notes: SYNOPSIS. Exposure to non-lethal doses of ultraviolet completely inactivates chloroplast development and chlorophyll synthesis in Euglena gracilis var. bacillaris and in the Z strain. Treatment with visible light immediately following UV reverses the inactivation completely. The presence of chloroplasts is not necessary for this inactivation since similar results are obtained with light-grown cells (containing chloroplasts) and dark-grown cells (lacking chloroplasts).

Notes: SYNOPSIS. Strains of Trypanosoma rhodesiense resistant to atoxyl and to antrypol respectively were allowed to multiply in the blood of mice and were also maintained for some hours in the gut of tsetse flies. They failed to acquire cross-resistance as shown by tests with the respective drugs given singly and in combination to infected mice.

Notes: SYNOPSIS. Paramecium multimicronucleatum was grown in a buffered desiccated lettuce medium maintained at pH 7.5, with Aerobacter aerogenes the main bacterial source. The maximum expansion in length and width was at pH 6.0; the minimum expansion in length and width at pH 8.5. The paramecia were usually stouter at pH levels 〈 7.0 except at pH 5.5 and generally more slender 〉 pH 7.0.The pH of the medium affected the size of food vacuoles as indicated by the fact that the maximum food vacuolar diameter was at pH 6.0, the minimum at 7.0.The fastest and greatest expansion of food vacuole diam. was at a relative viscosity of 8; the minimum food vacuolar diam. was in controls (without gum arabic) having a viscosity of 1.3.

Notes: SYNOPSIS. Trypanosoma granulosae n. sp. was found in the salamander, Taricha granulosa twittyi, from Dutch Bill Creek, Sonoma County, California. This polymorphic trypanosome has an anterior nucleus containing a definite endosome. The kinetoplast is rod-shaped and never contained within a vacuole. Myonemes are occasionally seen in slender individuals.

Notes: SYNOPSIS. Balantidium coli was cultured for 4 months in Dobell-Laidlaw's medium. About 10 specimens of monsters were found in the preparations (Chatton-Lwoff silver impregnation technique). One individual showed a tendency to polystomy. One doublet of Balantidium caviae (?) in preparations treated by the same technique was found in a population from a guinea pig.The monsters of Balantidium coli are either single distomic individuals or doublets (homopolar or heteropolar).The infraciliature of the monsters shows different degrees of deviation from the normal pattern. No reorganization field during the formation of additional cytostomes was observed, which agrees with the data on normal stomatogenesis. This process is very similar in both normal specimens and monsters and is characterized by the arrangement of radiating kineties surrounding the anlage of the cytostome and, evidently, by invagination of this area which later forms the peristome. The fate of single monsters and that of homopelar doublets is unknown. The heteropolar monsters are considered non-viable because the arrangement of the kineties in both presumptive daughters contradicts the rule of desmodexy (Chatton-Lwoff).The occurrence of the monsters in cultures may possibly be explained by the action of acriflavine which is mutagenic for Escherichia coli, or by gentian-violet which inhibits fission of sea urchin eggs.This paper apparently constitutes the first presentation of anomalies of the infraciliature in parasitic ciliates.In addition the exact arrangement of the kineties and kinetosomes at the posterior pole of Balantidium coli is described.

Notes: SYNOPSIS. A nonpathogenic strain of Histomonas was used in an attempt to immunize young turkeys against blackhead. Rectal inoculation of several thousand nonpathogenic histomonads on 2 or 3 consecutive days afforded considerable protection against modest rectal challenges with pathogenic histomonads 3 to 6 weeks later, but was much less effective against pathogenic histomonads introduced by feeding eggs of Heterakis gallinae. It is believed that an immune barrier limited to the surface of the cecal mucosa was established, and that the larvae of the cecal worms often penetrated this barrier before liberating their histomonads, thus permitting blackhead to develop. Immunization by the introduction of nonpathogenic histomonads with Heterakis eggs was not satisfactory. Apparently, the nonpathogenic organisms introduced in this way were too few to assure formation of an intact barrier.

Notes: SYNOPSIS. Podophrya collini was fed homozygous killer Paramecium aurelia (containing kappa particles DNA). The rate of giant formation in the suctorian population was then determined; controls were fed homozygous sensitive P. aurelia. No difference in the rate of giant formation was observed; the DNA contribution by the kappa particles was not enough to induce a higher rate of giant formation. Cultures of P. collini containing only animals of known uniform age were then fed controlled numbers of Tetrahymena pyriformis or sensitive P. aurelia after these ciliates had been pretreated with guanylic acid, 8-azaguanine, commercial DNA or DNA isolated from Tetrahymena. Giant formation was increased after guanylic acid pretreatment, reduced after the 8-azaguanine pretreatment, and unaffected after DNA pretreatment over a 5-day test period. The changes in rate of giant formation are clearly caused by pretreatment agents. These agents reach the suctorian's metabolism via the food ciliates' food vacuoles before they are altered in the food vacuole.

Notes: SYNOPSIS. Polytomella caeca utilizes as sole carbon sources in chemically defined media: acetate, propionate, butyrate, valerate, pyruvate, succinate, ethyl, butyl, amyl, and hexyl alcohols. Glyceraldehyde and α-ketoglutarate sustain very small populations. Caproate, caprylate, fumarate, malate, propyl, heptyl, and octyl alcohols and the iso-compounds iso-butyrate, iso-butyl and iso-hexyl alcohols are inadequate.Acetate is not assimilated 〈pH 5.0, propionate and butyrate 〈pH 6.0, and valerate 〈pH 7.0. Optimum for utilization of succinate is pH 3.0, for pyruvate pH 4.0, utilized also at pH 2.0 Fatty acids are utilized dissociated; succinate and pyruvate are utilized undissociated. Alcohols are assimilated throughout pH 4.0–7.4, except hexanol at pH 7.4. Alcohol availability is proportional to molecular length-1.pH after growth of fatty acid media is 8.4 ± 0.4; stable in pH 2.0 pyruvate and pH 3.0 succinate media; 3.5 ± 0.3 in alcohol media with initial pH 〈6.0. Longer alcohols cause less pH decrease during growth.Acetate concentrations 〈0.2% do not support maximum populations; concentrations of 0.2–1.0% do. pH after growth increases in these media to pH 8.5 with maximum populations.Malate, fumarate, α-ketoglutarate, and lactate seem not to penetrate the cell, but are metabolized by homogenates. Methylene blue reduction by homogenates indicates the presence of lactic, malic, succinic and α-ketoglutaric dehydrogenases, fumarase and glutamic transaminase. Extracts contain Embden-Meyerhof phosphate esters, ATP, and ADP.

Notes: SYNOPSIS. An immunity to reinfection with E. bovis was demonstrated in 3 experiments involving 60 calves. This immunity develops rapidly, as indicated by resistance to a challenge given 14 days after the immunizing inoculation. In 3 groups of 3 to 6 young calves each, immunity was still present to a moderate degree 2 to 3 months after inoculation; in one group of 5 animals about a year old there was apparently a high degree of immunity about 7 months after the last inoculation. In one experiment an immunizing inoculum of 10,000 oöcysts did not produce as much immunity as 50,000 oöcysts. In 2 experiments there appeared to be little difference in the immunity produced by a single inoculation of 50,000 as compared with 100,000 oöcysts, but inoculation with 100,000 oöcysts, resulted in substantially longer and more severe illness than 50,000 oöcysts. There appeared to be no appreciable difference in clinical symptoms or development of immunity between calves given a single immunizing inoculum and those given the same number of oöcysts in 5 equal inocula on successive days. Treatment with sulfamethazine and sulfamerazine (Merameth) 13 to 15 days after inoculation alleviated the clinical symptoms of coccidiosis without interfering appreciably with the development of immunity. In one experiment with 7 calves, no beneficial effect was noted from 1 or 2 transfusions of 500 ml. of plasma and leucocytes from immune calves into 4 calves 1 and 12 days or 11 days after a challenge inoculation.

Notes: SYNOPSIS. Experiments were carried out to determine if the course of infection with Plasmodium cathemerium was changed when the temperature of incubation of the duck embryo host was lowered. At 30° C. the infection developed more slowly and never reached the peak seen in infected embryos incubated at 37° C. If infected embryos at 30° were returned to 37° C. the resultant parasitemia developed similarly to that usually seen in this host at the latter temperature. Studies of the periodic behavior of the parasite at 30° C. and 38° C. revealed no differences in the time of segmentation. Merozoite counts were unchanged. The reduced parasitemia in embryos at 30° C. may result from reduced ability of the parasite to penetrate new host cells.

Notes: SYNOPSIS. California ground squirrels (Citellus beecheyi) were found to be infected with trypa-nosomes whose most striking morphological features are an unusually large kinetoplast and a long, tapering posterior end. The total length is 25.2 μ, and body length is 18.0 μ. This “lewisi”-type species is compared with other trypanosomes reported from American ground squirrels, but a specific diagnosis is not made because the life cycle has not been observed and because morphological features of trypanosomes are known to vary widely under differing environmental conditions.

Notes: SYNOPSIS. The basal apparatus of the flagella and kinetoplast in Leishmania donovani have been studied with the electron microscope. The flagellar fibrils extend into the body of the protozoan to form the kinetosome. At the point of origin of the flagellum, the pellicle invaginates to form a kinetosomal vacuole around the kinetosome. The kinetoplast is formed by a transversely elongated banded structure, surrounded at some distance by a double layered kinetoplast membrane. There is no apparent connection between the kinetosome and the kinetoplast.

Notes: SYNOPSIS. Starvation of Isotricha prostoma for 72–96 hours decreased the cellular amylopectin granules and facilitated the microscopic search for bacterial feeding. I. prostoma selected and ingested only certain rods from among many types of rumen bacteria. In order to isolate the bacteria important as a food source for Isotricha, the starved protozoa were allowed to feed on mixed rumen bacteria, washed, and the crushed protozoan contents quickly cultured for bacteria. Several strains of bacteria were isolated in pure culture. Three of the rod strains isolated were rapidly ingested by I. prostoma when fed to the ciliate. In a monobacterial culture I. prostoma divided once before succumbing.

Notes: SYNOPSIS. Cultures of Trypanosoma theileri were obtained at 36° and at 37.5°C. in a blood-lysate medium inoculated with blood from three dairy cows showing subnormal milk production. The organisms were first seen after 4 days in the first subculture, reached a maximum number of about 500,000 per ml. on the 4th day of the second subculture, and attained about this same number on the 4th day of subsequent transfers. Crithidial forms predominated but trypanosomes of the blood-stream type were also numerous. Cultures were not obtained from cows with normal milk production. The infected cows, although free from helminth parasites, showed a marked eosinophilia.

Notes: SYNOPSIS. A new species of Paramecium, P. jenningsi, n. sp., from South India, is described. It is like P. aurelia except that nuclei are larger, the cell size is somewhat larger, and the macronuclear anlagen (“placentae”) have long-persisting chromatinic centers.

Notes: SYNOPSIS. The nutritional requirements of 3 isolates of Prymnesium parvum (2 Israeli, 1 Scottish) included vitamin B12 and thiamine. For comparison, 2 other brackish chrysomonads were studied: Monochrysis lutheri isolated by Droop in Scotland and Isochrysis galbana purified by McLaughlin from a culture obtained from the Plymouth laboratory.The isolates of Prymnesium parvum and Isochrysis galbana had a molecular B12 specificity like Ochromonas malhamensis: no response to Factor B, pseudovitamin B12, Factor A or Factor H. M. lutheri, in contrast, responded to pseudovitamin B12, Factor H, and Factor A.Thiamine was essential; 1.0 μg.% allowed full growth of P. parvum. The NaCl concentration for good growth was 0.3–5.0%; growth was possible from 6–12%. Dark growth was not achieved.Ammonia, as suggested from its use in suppressing outbreaks of P. parvum, was sharply inhibitory, less so at high concentrations of NaCl or at acid pH.Nitrate, ammonia, arginine, asparagine, methionine, histidine, alanine, glycine, serine, proline, leucine, isoleucine, tyrosine, aspartic and glutamic acids, acetylurea, and creatine served as nitrogen sources in both acid and alkaline media.The phosphate requirement of P. parvum and M. lutheri and Isochrysis galbana was satisfied by inorganic phosphate, commercial glycerophosphate, yeast adenylic acid, cytidylic acid, monoethyl phosphate, and riboflavin monophosphate.Laboratory cultures in defined media of the isolates of P. parvum were toxigenic to Lebistes and Gambusia. Culture fluids from alkaline media were more toxic than those from acid media, as previously noted in Israel.Culture media suitable for production of large quantities of these organisms were developed.

Notes: SYNOPSIS. Certain aspects of the metabolism of a Trichomonas batrachorum-type flagellate from the cecum of swine were studied. This trichomonad (1) oxidized glucose, mannose, maltose, sucrose, and inulin, (2) was incapable of oxidizing Krebs' cycle intermediates, (3) possessed peroxide-splitting capabilities, (4) was inhibited by only iodoacetate and arsenite, and (5) formed acid(s) aerobically. Although there was no effect on oxygen uptake, pyruvate and lactate increased the anaerobic evolution of gas(es). In addition to CO2, other gas, not absorbed by KOH, was produced anaerobically.Compared with other porcine trichomonads, the metabolism of this small trichomonad resembles most closely that of the large cecal trichomonad, T. suis. However, the smaller trichomonad had a generally lower respiratory rate, a slightly lower optimal pH, and failed to oxidize fructose, galactose, lactose, raffinose, and trehalose.

Notes: SYNOPSIS. The “dry” silver method is redescribed with special attention to the possible difficulties encountered in its use. This method first revealed the silverline or neuroformative system of the ciliates, and is considered the best method for the demonstration of this structure. The valuable results obtainable with this technique are pointed out and illustrated with appropriate photomicrographs.

Notes: SYNOPSIS. It has been assumed by others that green euglenas and derived bleached forms are physiologically equivalent except for chlorophyll and plastids. Some workers, however, have remarked upon differences which might depend on the mode of bleaching.Several hitherto undescribed chlorotic substrains of E. gracilis var. bacillaris were examined for pigment alteration, growth under a variety of conditions, and ability to withstand high temperature. These studies indicated physiological variation in the different chlorotic substrains. Although all were apparently chlorophyll-less and aplastidic, only one seemed completely achromatic. The carotenoid content of others varied. Metabolic changes manifested by altered pigmentation may reflect enzymatic variation caused by the chlorosis-inducing agents.

Notes: SYNOPSIS. Thin sections of Amoeba proteus, fixed in osmium tetroxide and embedded in methacrylate, were examined in the electron microscope. The fine structure of various protoplasmic components is described. The plasmalemma, or cell membrane, varies in thickness and structure. These variations may be due to variations in physiological state, or they may be due to differences in preparation. Along its cytoplasmic edge is always present a definite line approximately 0.01 to 0.02 μ thick. The mitochondria, or beta granules, exhibit a structure similar to that of the mitochondria of several other protozoa and comparable to that of the mitochondria of other animals. In definite association with the membrane of the food vacuole are dense, rounded particles which in size are below the limit of resolution of the light microscope. Such dense particles are much less frequently present in the hyaloplasm and in association with the plasmalemma. A possible relationship to the neutral red granules associated with food vacuoles of Paramecium is suggested. The contractile vacuole possesses a thin membrane surrounded by a much thicker circum-vacuolar zone of irregular strands which may form a three-dimensional network around the membrane. This may represent the contractile element of the vacuole. A single layer of mitochondria is closely apposed to the circum-vacuolar zone. Many small vacuoles and irregular vesicles are present throughout the cytoplasm. At times there occur groups of small, thin-walled vesicles, which may correspond to an endoplasmic reticulum. The nuclear envelope consists of a thick inner porous layer and a thinner outer layer that is continuous yet is marked by the presence of numerous small annuli, each apparently surrounding a pore. In its structure, this outer layer appears to correspond to the entire nuclear envelope of many other cell forms.

Notes: SYNOPSIS. Irradiation of Stentor coeruleus with Xray doses of 150–300 kr inhibited growth in size and fission. The irradiation also led to the development of structural abnormalities, which appeared about a day after irradiation. The inhibition of growth and fission was independent of the oxygen concentration during irradiation, but the abnormalities were produced at lower doses in nitrogen than in air. Regeneration of parts removed by cutting occurred even at the highest doses at essentially normal rate even during the period when over-all growth was completely inhibited. The conclusion is drawn that delay in fission by radiation is a secondary consequence of inhibition of growth and not a consequence of blocks in the specific morphogenetic processes required for division.

Notes: SYNOPSIS. A description is given of the formation of an unusual type of achromatic figure by two very long, narrow centrioles. The unique manner in which this structure functions in chromosomal movement is explained.

Notes: SYNOPSIS. Pelomyxa illinoisensis exhibits several phenomena of an interesting and uncommon nature, such as the presence of polar granules and the appearance of chromosomes through most of the resting and dividing stages of the nucleus. For these reasons and because of the importance of the nucleus as a stable characteristic in the taxonomy of amoebae, this study of the nucleus and nuclear division was undertaken.Culture methods were the same as those used for P. carolinensis. Best fixatives for nuclei were Carnoy, Flemming, 10% formalin, Duboscq-Brazil, Schaudinn and 2% osmium tetroxide. The body shape of P. illinoisensis in nuclear division is correlated with the stage of nuclear division and resembles the same stages in Amoeba proteus and P. carolinensis, with the exception of a ragged appearance of the cytoplasm of organisms containing prophase nuclei and the halo-like appearance of the pseudopods in those containing metaphase nuclei. The condensation of resting nuclei when subjected to acidified methyl green, reported by Kudo (18), occurred with all fixatives used with the exception of 10% formalin and 2% osmium tetroxide. The metaphase nuclei have a disk of polar granules on either side of the equatorial plate with fibers running from them to the chromosomes. The nature of these granules is unknown. Similarities and differences between P. illinoisensis and P. carolinensis are discussed.

Notes: SYNOPSIS. Inhibitors, acid production, and substrate utilization by 4 strains of Tritrichmonas foetus (BP-3, BP-4, A-1, and A-2) were studied manometrically. All used glucose, galactose, mannose, fructose, sucrose, maltose, trehalose, glycogen, starch, lactate, and pyruvate. Strain A-1, with the highest aerobic and anaerobic endogenous rates, used these substrates less than did the others. Strain BP-3 did not use lactose; strains BP-4 and A-2 did not use raffinose aerobically and only slightly anaerobically; strain A-1 used both nearly as well as maltose and sucrose. All were strongly inhibited by iodoacetate and, if tested in the presence of glucose, aerobically or anaerobically, by fluoride, arsenite, hydroxylamine, and 8-hydroxyquinoline. Aerobically, 2,4-dinitrophenol produced stimulation which was greater in the presence of glucose; anaerobically, it produced inhibition which was, in some cases, comparable to the effects produced by the other inhibitors. Fluoride, arsenite, azide, and hydroxylamine, although producing insignificant inhibitory effects on endogenous O2 consumption, reduced and, in some cases, abolished motility of all strains. All 4 strains produced acid under anaerobic and aerobic conditions; strain A-1 produced more than the others. Lactic acid accounted for 30–51% of the acid produced in all strains.Strain A-1 more closely resembled the nasal trichomonad of swine (strain PN-610) than did strain BP-1. (Doran(3)). The writer believes that the swine nasal strain is a highly adapted strain of T. foetus.

Notes: SYNOPSIS. Vorticella microstoma was grown non-axenically and axenically at pH 6.4. Vorticellas were maintained indefinitely on Bacillus cereus in a medium composed of Proteose-Peptone, Cerophyl, and the filtrate from boiled wheat kernels. Prolific growth occurred in 2-membered cultures. A medium containing hydrolyzed gelatin, aqueous liver extract, yeast nucleic acid hydrolysate, glucose, and penicillin is recommended for axenic growth.The potential value of vorticellids as research tools is discussed together with metabolic implications of supplementing sterile Proteose-Peptone broth with natural substances in particle form. The ineffectiveness of adding tryptophan, thiamine, glycine, and chelating agents to the axenic medium was considered. Refinements of the axenic medium are on trial.

Notes: SYNOPSIS. 45% of the agamid lizards captured in the Harbel area of Liberia harboured haemosporidia. These were Haemamoeba (=Plasmodium) agamae, H. giganteum and a Haemoproteus.A full description of H. agamae and H. giganteum blood forms is made and the discovery is reported of exo-erythrocytic forms of H. agamae in the spleen and of H. giganteum in the brain and liver. One oöcyst of H. agamae is reported in Aedes aegypti.

Notes: SYNOPSIS. A brief introduction to a projected series of papers precedes the description of Plistophora collessi n.sp., parasitic in the egg follicles of Culex (Culex) tritaeniorhynchus Giles and C. (C.) gelidus Theobald. This microsporidian causes degeneration of the oöcyte, nurse cells and epithelium of the invaded follicle, within the distended limiting membrane of which a spherical cyst is formed. Such cysts measure from 45 to 340 μ (av., 220 μ) in diameter, and contain many sporonts. These average 50 μ in length and breadth and ultimately contain up to 300 (av., 200) sporoblasts, each of which develops into a single tiny (av., 2.5 by 1.4 μ) spore. Myriads of spores (many of them remaining grouped within the individual sporont membranes) pack the ripe cysts, which burst out into the lumen of the ovary in place of eggs, often associated in pairs, less commonly in groups of three, still enveloped by the follicular tube membrane. They roll about freely in the lateral and common oviducts, and are probably liberated, some of them eventually to be ingested by mosquito larvae, when the infected females attempt to oviposit.

Notes: SYNOPSIS. The pigments of Euglena gracilis var. bacillaris change when cultures of light-grown organisms are placed in the dark; the alterations in spectrum indicate the formation of a pheophytin-like substance from chlorophyll. This pheophytin-like compound is not an artifact of extraction and separation of the pigments; the spectral changes occur in the intact cells. The “dark” pigment is not yet definitely characterized. Formation of this material on dark adaptation seems dependent on the nutritional history of the cells.

Notes: SYNOPSIS. Two strains (1B and 1P) of Plasmodium relictum isolated from pigeons could be easily passed serially in pigeons by transfer of infected blood. What appeared at first to be a qualitative difference between the infectiousness of gametocytes of strain 1P in pigeons and of gametocytes of the strain after being adapted to canaries (1P1) was found to be only a quantitative difference in their infectivity for mosquitoes. Earlier work had indicated that gametocytes of strain 1P were noninfectious for mosquitoes. The experiments reported here show that Culex tarsalis is highly susceptible to gametocytes of both strains 1B and1P and that Culex pipiens is slightly susceptible to gametocytes of strain 1P.The susceptibility of 72 pigeons (belonging to 24 varieties, plus mongrels and 3 species hybrids) to sporozoites of strain 1P1 was tested; only 5 transient infections lasting no more than two days and 3 subpatent infections were obtained. Similar results were obtained with sporozoites of strain 1B.The two strains are similar in both mosquito and avian hosts except that 1B is more highly infectious for C. pipiens and C. tarsalis than 1P. There is evidence that one or both of these strains may be Plasmodium relictum matutinum, Huff(7). A proposed hypothesis indicates that (1) various species of mosquitoes have different susceptibilities, (2) various species of avian hosts are infectious to different degrees, and (3) that the probability of a mosquito of a given species being infected from a given species of parasite may be expressed by the degree of overlap between the normal curves of susceptibility of the mosquito and infectiousness of the gametocytes in the pertinent avian host. The susceptibilities of pigeons to sporozoites of the two strains of parasites and of mosquitoes to gametocytes produced in pigeons are so low that it can be questioned whether these strains could persist in nature without the presence of other avian hosts on the one hand possessing greater susceptibility than the pigeon to sporozoites and on the other hand contributing more to the infectiousness of the gametocytes than the pigeon does.

Notes: SYNOPSIS. A method for the isolation of trichocysts and cilia from whole paramecia is given. Trichocysts, cilia, mitochondria, and other particulates have been identified in homogenates and their numbers in different centrifugal fractions determined. Four antigens extractable from one strain of Paramecium have been studied by gel-diffusion techniques: Antigen 1, heat-stable, derived from trichocysts; antigen 2, not associated with any cellular particulate in homogenates; antigen 3, obtained in large quantities from the mitochondria; antigen 4, the antigen correlated with serotype, is derived mainly from the cilia and probably from the body wall and having the properties of a protein.

Notes: SYNOPSIS. Eimeria carolinensis n.sp. (Sporozoa) is described from oöcysts in the feces of the white-footed mouse, Peromyscus leucopus (Rafinesque) taken in the vicinity of Durham, North Carolina. The oöcysts are ellipsoidal to elongate ellipsoidal, 14–19.5 × 10–13 μ, mean of 17.6 × 11.3 μ. Micropyle absent. Oöcyst wall composed of 2 layers. A refractile granule present but no oöcyst residuum. Sporocysts ovoid almost filling the oöcyst. Small Stieda body present.

Notes: SYNOPSIS. Crosses between serine requiring and non-requiring clones from natural habitats give rise to progeny that are numerically equally distributed between the two categories. Most of the progeny from crosses between two serine requiring parental clones require serine with a few segregating out that do not need the amino acid. These data indicate that the gene or genes controlling the serine non-requirement are recessive to the wild type which requires serine. Growth of the F1 progeny was highly variable. Some clones failed to survive on serine deficient media and were therefore tentatively assigned the genotype +/+. The remaining clones were of two classes: one grew slowly on serine deficient media and was given the genotype of the heterozygote, +/s; the other grew without serine, hence was given the double recessive genotype, s/s. The F2 progeny from matings of s/s and s/s need no serine whereas the cross of +/s and s/s gave equal numbers of serine requiring and serine non-requiring progeny. The cross of two heterozygotes, +/s and +/s, yield progeny approximating the 3:1 ratio in favor of serine requiring clones. Crosses at the F3 level produced non-viable offspring in all cases except one. Progeny from this cross with the genotype s/s were mated giving rise to F4 progeny all of which grew without serine. The data support an outbreeding economy for this organism with selection in favor of the heterozygote. Although the data seem to favor a single-gene hypothysis, suppressor genes may be involved. With selection favoring the heterzygote, distorted genetic ratios make the data difficult to analyze.

Notes: SYNOPSIS. Intracardial inoculation of 1–10 million L. donovani in 0.1 ml. of ground spleen suspension from an infected animal (hamster) results in a uniform rise of parasite numbers in the untreated animal over the first 8 days after the inoculation. This rise is highly consistent from experiment to experiment.Treatment is accomplished by parenteral injection of a compound for 6 successive days in this time interval, starting 24 hours after inoculation.No known active compound in proper dosage (sodium stibogluconate, pentamidine, fuadin) has failed to show a significant suppression of the expected rise in parasite numbers. No known inactive compound has had any effect on the course of the infection.The dosage-response curve for the active compounds suggests that the method is a sensitive one. Since it takes only 8 days to complete, it is economical as well.