ALBERT

Notes: SYNOPSIS. In cultures of Trypanosoma conorhini the authors have detected “cyst-like bodies” (CLBs) that, in the initial phase, have the appearance of 2 or more overgrown crithidiae fused together; after disorganization of the internal structure of the parent flagellates and division of their organelles, new crithidiae are formed within the CLB. The wall of the CLB consists of an irregularly thick layer of cytoplasm surrounded by the periplast of the parent flagellates and a true cystic membrane is not evident. The daughter crithidiae eventually escape from the CLB leaving the periplast and other residues of the parent flagellates. It is suggested that this represents a method of reproduction entirely different from binary or multiple fission, that is probably common to other trypanosomes of the Section STERCORARIA, and that it may provide for genetic exchange even if it is not a true sexual process.

Notes: SYNOPSIS. During conjugation of Kahlia the micronuclei divide 3 times before synkaryon formation and 2 times thereafter. The 1st division is heterotypic, as in other ciliates, in that it is characterized by the parachute stage. Following this stage, 24 to 26 bivalents and 4 to 8 univalents appear in the micronuclear area. When the bivalents move to organize the metaphase plate, the univalents lag behind and fail to reach the equatorial region at the same time. Due to this irregular behavior of the univalents there is no distinct metaphase in the first meiotic division. A few meiotic irregularities including the breakdown of the spindle apparatus have been observed. During the breakdown of the spindle apparatus the chromosomes fuse into irregular bodies which resemble the chromosome aggregates observed during the somatic divisions. Generally 1, and rarely more, of the products of the 1st division enter the 2nd division. The spindles of this division are oriented parallel to the long axis of the cell, and 1 of the daughter nuclei reaches the partition membrane separating the conjugants. This nucleus alone undergoes the 3rd division, resulting in the formation of gametic nuclei. Reciprocal exchange and fusion of the gametic nuclei result in the synkaryon formation. The synkaryon divides twice in rapid succession resulting in 4 daughter nuclei; 1 of them degenerates and 2 condense and become functional micronuclei. The chromosomes of the remaining daughter nucleus resemble in size and number the bivalents of the 1st meiotic division. They become polytenic and then reproduce to give rise to the polyploid macronucleus. The development of the macronucleus has been traced from a single diploid set of chromosomes and no evidence has been found for the formation of genetic “subnuclei.” During the early stages of the development of the macronuclear anlage, somatic pairing forces keep the homologs together, while in the later stages these forces cease to exert influence. While these changes are in progress the old macronucleus; breaks up into small irregular polymorphic bodies which are scattered throughout in the cytoplasm. The exconjugants usually encyst and the cysts are not favorable for detailed cytologic study.

Notes: SYNOPSIS. In young first generation schizonts of E. bovis, the nuclei appeared to have a random distribution. In calves killed 8 days after inoculation some of the schizonts had the nuclei arranged in a single layer at the periphery, with a few infoldings of this layer into the interior. In further development, such ingrowths of the nuclear layer resulted in the formation of compartments of varying size. In schizonts of calves killed 12 days after inoculation spherical or ellipsoidal bodies (blastophores), about 5–20 μ in diameter with a single peripheral layer of nuclei were formed. Merozoites developed as radial outgrowths from the blastophores, leaving residual bodies of variable size, which later disappeared. The response of the host cell to the presence of the schizont was characterized by marked growth of both the nucleus and cytoplasm. The nucleolus became greatly enlarged, and the chromatin was distributed in relatively fine granules. In the host cell cytoplasm, 2 concentric layers were observed; the inner was more dense than the outer. After growth of the schizont was completed its host cell was stretched into a thin covering layer about 1 μ thick. In some schizonts, the host cell disintegrated, and the schizont was then invaded by eosinophils, macrophages and other cells, which eventually destroyed the merozoites.

Notes: SYNOPSIS. Blood smears from 133 Rio Grande wild turkeys Meleagridis gallopavo intermedia live-trapped in the Welder Wildlife Refuge in south Texas, were examined for blood parasites. All of the 63 immature turkeys and 63% of the 70 adult turkeys were infected with Haemoproteus meleagridis. The infections were light, half the cases having less than 5 infected cells per 10,000 red blood cells. Infection with H. meleagridis caused significant enlargement of the host RBC. Other parasites specifically searched for but not found were Leucocytozoon, Trypanosoma, Plasmodium and microfilariae.

Notes: SYNOPSIS. The fine structure of the tomite stage of Hyalophysa chattoni was examined with particular attention to its kinetal apparatus.The pellicle, thick and dense compared with that of other ciliates, is formed of three layers. The inner layer is composed of short fibrils oriented perpendicular to the surface.The cytoplasm around the oral passage and beneath falciform field 8 is crowded with dense inclusion bodies of unknown function. Dorsal to the oral passage is the rosette, a disc-shaped organelle subdivided by septa in the form of incomplete radii about a central chamber containing a tuft of cilia. The septa are composed of 3 membranes enclosing a fine layer of cytoplasm. At their inner ends 20 mμ fibers run dorsally and ventrally. Dense clumps of fibrous material line the luminal surface of the septa.Rows of fusiform trichocysts parallel the kineties. The trichocysts are composed of a finely periodic, moderately electron-dense material surrounded by 20 mμ fibrils oriented along the long axis of the trichocyst. Between and below the kinetosomes and the rows of trichocysts are electron-dense vesicles 300 mμ in diameter and bounded by a loose membrane. The large “trichocysts,” the “gros trichocystes” of Chatton and Lwoff, whose appearance heralds the beginnings of trichocystogenesis, prove to be canaliculi opening to the surface.Four separate ciliary membrane systems—the oral ciliature (XYZ), falciform field 8, falciform field 9, and the ogival field—are located on the ventral surface of the tomite. Each differs from the others and from the somatic kineties in the fibrillar organization around its kinetosomes.In the somatic kineties the kinetodesmos is a dense, periodic fiber which is formed of stacks of up to 18 subfibers, each arising from the base of a kinetosome. The kinetosomes are short (300 mμ) and contain dense central granules. In some kineties, alternating between the kinetosomes, are elliptical kinetosome-like structures which do not bear cilia and perhaps provide a reservoir of kinetosomes for future growth of the kinety.

Notes: SYNOPSIS. The life cycle of the true slime mold Physarum polycephalum includes 2 vegetative stages: the multinucleate coenocytic plasmodium and the uninucleate amoeba. A clone of amoebae established from a single spore does not normally yield plasmodia. Plasmodia are formed when amoebae from particular clones are mixed; thus plasmodium formation is said to be controlled by a ‘mating-type’ system.Previous work by the author with a sample of P. polycephalum derived from a single source revealed that 2 mating types were present and were determined by a pair of alleles at 1 locus. The present paper reveals the presence of 2 more mating types in a sample of P. polycephalum derived from a different source and provides evidence that these are determined by 2 alleles at the same locus as the other 2.Evidence for the presence of other inherited factors affecting plasmodium formation, the mode of action of these factors and possible explanations for the occurrence of plasmodia in single-spore cultures are also discussed.

Notes: SYNOPSIS. Transection and regeneration of Blepharisma intermedium initiate complex macronuclear activity and micronuclear division. Reversible condensation of the macronucleus is achieved by contraction which involves primary and secondary coiling. Primary coiling, evident in vegetative cells, is enhanced by pronounced constriction of the macronuclear extremities during regeneration. Secondary coiling is restricted to the period of contraction and is initiated at the ends of the mauonucleus. Condensation terminates the coiling processes and gives rise to an amorphous structure. Re-elongation of the macronucleus is not followed immediately by coiling. Micronuclear division begins early in regeneration, but the peak of visible activity is not reached until the 3rd through 5th hours.

Notes: SYNOPSIS. Lipids in aging cultures of Tetrakymena pyriformis were extracted at various times after inoculation, purified, and weighed or chromatographed on thin layers of silica gel. The total cellular lipid increased throughout logarithmic and early stationary phases but decreased sharply after 72 hr. The amount of one lipid class, probably the triglycerides, followed the same trends. It may be a cellular reserve.

Notes: SYNOPSIS. Rearing of cockroaches without sporozoan parasites of the Malpighian tubules permitted the 1st experimental infections reported for these organisms as well as study of the intracellular early stages of infection. Infectivity tests show that the route of invasion is peroral rather than transovarian; that fresh spores obtained from either the Malpighian tubules or the hindgut are infective; that fresh spores held in aqueous suspension for 36 hr are not infective; that all ages and both sexes of cockroaches are susceptible, although older cockroaches are more readily infected experimentally; that a single peroral dose of a few hundred spores is sufficient to produce infection; that the earliest signs of progressive infection in the Malpighian tubules appear 15 days after ingestion of spores; and that the infection, spread mainly by schizogony, is well established by 23 days. Spores are acid-fast. The PAS-positive spore membrane is not dissolved by 20-min treatment with hot KOH, but tests for chitin were inconclusive. The life history of the parasite is described. “Encapsulation” of the parasite has been observed. Electron microscope studies, the first reported for the class Haplosporea, show similarities of the cytoplasmic structure of this haplosporidian with that of some members of the sporozoan class Telosporea, though no specialized structures were seen. Finding of intracellular stages together with failure of interspecific infection attempts suggest that the microorganism should be placed in the genus Nephridiophaga Ivanic, 1937 with the specific name blattellae Crawley, 1905.

Notes: SYNOPSIS. A centrifugation procedure for removing Tetrahymena from mass cultures is described. This method offers the following advantages: (a) inexpensive apparatus, (b) the short period of time required for harvesting large numbers of cells, (c) lack of cellular damage, (d) the ability to obtain proven dilution with regard to the culture fluid, (e) nearly quantitative recovery of the cells, and (f) the ease of assembling and disassembling the apparatus for cleaning.

Notes: SYNOPSIS. Monocercomonas molae from the hindgut of the sunfish Mola mola is described. The host was taken from southern California coastal waters in October, 1964. The body of the flagellate is 8.0 × 10.7 microns. A single basal granule complex gives rise to 4 flagella, one of which is recurrent. The axostyle is relatively stout, with argentophilic granules, and possesses a periaxostylar ring. The capitulum of the axostyle continues into the sickle-shaped pelta, and the parabasal body is rod-shaped or lobed and roughly triangular in cross-section.

Notes: SYNOPSIS. The complete life history of a homothallic, dioecious strain of Volvox aureus was studied in axenic culture. Asexual reproduction occurs by repeated division of specialized reproductive cells (gonidia), inversion of the resultant mass of cells to form daughter colonies, and subsequent morphologic differentiation of new gonidia in these daughters. Male colonies lack gonidia; however, the posterior 2/3 of the cells in a colony function as male initials each of which enlarges, divides, and undergoes rudimentary inversion to form a packet of 32 biflagellate sperm. Evidence was presented for the homology of eggs and undivided gonidia. The penetration of young vegetative colonies by sperm and the subsequent formation of apparent zygotes in these colonies was described and figured. Zygote germination, including division and inversion of the germling, was described; the cytological nature of the zygote divisions was not determined.A substance, MIS, in filtrates of sexual cultures induced differentiation of male colonies; a bioassay for it was perfected. Bioassay colonies show a differential susceptibility to male induction by MIS which is a function of the particular stage of development; colonies 48 hr after release from parentals are optimally susceptible. MIS was reasonably stable to heat, non-dialyzable, and Sephadex gel filtration indicated a molecular weight 〉 200,000. MIS activity is destroyed by trypsin and pronase but is unaffected by chymotrypsin. MIS was successfully concentrated ∼37-fold by the Carbowax method. The patterns of differentiation in other species of Volvox are described and possibilities discussed for studies of cellular differentiation in the genus as a whole.

Notes: SYNOPSIS. Haemogregarina faiyumensis n. sp., a parasite of toads, Bufo regularis, in Faiyuni Province, Egypt, U.A.R., is described. In a survey of 689 toads from various localities in Cairo, Giza and Faiyurn provinces, only 3 out of 13 toads from Kom O Shim near Faiyum were infected. This species, known only by blood forms (most probably gametocytes) of two different staining reactions, is 13-17 μ long and 4-5 μ wide, with an average of 15.5 × 4.5 μ. The nucleus is typically subcircular and 3-5 × 3–5 μ, with an average of 4.5 × 3.9 μ.

Notes: SYNOPSIS. Haemogregarina boueti França, 1910, was found to be the commonest blood parasite in the common toad, Bufo regularis Reuss, in Egypt. The rate of infection was about 30% (of 689 toads examined).In properly fixed blood films, the parasites were almost exclusively intraerythrocytic. Most characteristic was the encapsulated “elongate” form averaging 22.3 by 6 μ with a more-or-less central nucleus and a pointed, slightly bent, posterior end. Infected red cells were conspicuously hypertrophied and their nuclei were markedly displaced and frequently broken into 2-4 parts.Young and growing blood forms as well as two types of hepatic schizonts are described for the first time.Schizonts of the first type develop in hepatic cells, are 28–30 μ in diameter and produce numerous elongate oval merozoites about 8 × 2.2 μ radially arranged around a residual body about 10 μ in diameter.Schizonts of the second type start their growth in erythrocytes but later complete their development as free bodies in the liver sinusoids. When mature, they are 32–35 μ in diameter and produce a larger number of thin merozoites about 8 × 1.5 μ, surrounding a larger residual body about 19 μ in diameter.

Notes: SYNOPSIS. Haemogregarina pestanae França, 1910, is apparently rare in Egypt, having been found in 1 toad Bufo regularis Reuss out of 689 examined. Capsulated capped, young thin, and young and advanced broad forms were present in the peripheral blood. Schizogony occurred in the liver. Two types of schizonts were present—macroschizonts producing 150 or more elongate oval merozoites surrounding a large residual body, and microschizonts producing 60 or less banana-shaped merozoites often radiating from a small, eccentric residual body.Merozoites of the first type developed into a large broad form representing early schizonts of the second type. The latter developed into thin young intraerythrocytic forms and apparently later into encapsulated capped gametocytes. H. pestanae, H. aegyptia and H. tunisiensis all occur in toads (Bufo regularis for the first two, and B. mauritanicus for the third), and produce characteristic encapsulated looped gametocytes in peripheral blood. The capsules contain dark-staining material condensed into a single well-developed cap in H. aegyptia and 1 or 2 much smaller caps in H. pestanae; this material is scattered regularly around the parasite in H. tunisiensis. The capsule of H. pestanae is more or less cylindrical along most of its length, more slender and slightly shorter than the regularly oval capsule of H. tunisiensis or the spindle- or egg-shaped capsule of H. aegyptia.

Notes: SYNOPSIS. Spathidium spathula irradiated with 0 to 55 kr of × rays showed one or more of the following kinds of behavior: (1) Death of an undivided cell (primary death); (2) death of a descendant of an irradiated cell (secondary death); (3) permanent injury including one or more of the following: low daily division rate, excessive macronuclear enlargement, total loss of micronuclei, cytostome replication, heavy pigmentation, and decreased motility; (4) temporary division retardation for 1 to 2 days followed by apparent complete recovery; and (5) no apparent injury. The first 3 kinds of behavior increased with increasing dosage from 15 to 25 to 55 kr. At 6 kr only the last 2 categories were observed. The LD50 for 8 days was 46 kr for both primary and secondary death, or 60 kr for primary death alone.Micronuclear number varied greatly following irradiation in lines showing either permanent or temporary injury. Two different responses occurred: (1) The micronuclear number averaged about twice the normal number of 20 with a large range (0 to 360) 1 day after exposure. The number gradually decreased during the next 2 days; (2) some cells lost all micronuclei following irradiation, the incidence increasing with dose. At 55 kr complete loss of micronuclei occurred in 96% of the surviving lines.

Notes: SYNOPSIS. Exchange of cytoplasm in Tetrahymena pyriformis, syngen 1, has been demonstrated by growing cells of 1 mating type in medium supplemented with H3-uridine or H3-histidine, washing, mixing with cells of an unlabeled, starved mating type, sampling conjugants at different times, and preparing autoradiographs. It was found that cytoplasmic interchange begins soon after the mates unite, and has become extensive before the end of the 1st prezygotic prophase (micronuclear crescent stage). When the RNA in one mating type had been labeled with H3-uridine, the activity was distributed almost evenly between the mates by late stages of conjugation. These results are consistent with electron micrographs of this syngen showing small pores in the attachment region of the mates, and many free ribosomes in the cytoplasm (8,11). By contrast, when protein in one mating type had been labeled with H3-histidine, these cells at late conjugation remained about twice as active as their originally unlabeled mates, presumably because of the physical characteristics of some structures which incorporated the amino acid (for example, cilia and membranes of the cell surface; cytoplasmic bodies, such as mitochondria, larger than the pores). That the radioactivity in the originally unlabeled cells came from their mates and not from the environment is indicated by the continued presence of inactive non-conjugants after 1 and 2 days in the mating type mixtures. Other cells which did acquire small amounts of active cytoplasm probably had engaged in abortive conjugation, separating from labeled mates before forming and exchanging pronuclei.

Notes: SYNOPSIS. A major difference in heme content was found between leishmanias and leptomonads of Leishmania donovani. When tested with a fluorescence method for heme, leishmanias gave a negative response whereas leptomonads fluoresced brightly. Studies on the terminal respiration of L. tarentolae leptomonads by absorption spectra assay and respiratory inhibitors indicated the presence of cytochromes. Lactic dehydrogenase could not be detected in the leptomonad stage nor could it be found in any other hemoflagellate culture form tested.

Notes: SYNOPSIS. The fine structure of various stages in the life cycle of Theileria parva is described. The appearance of the parasites suggests that there may be a double macroschizogony cycle. Micromerozoites are produced by a process of budding off from the body, known in light microscopy preparations as the residual body.

Notes: SYNOPSIS. A pure strain of Eimeria debliecki (University of Illinois strain A) established from a single oocyst was used to determine the endogenous cycle. Young parasite-free pigs 2 weeks to 3 months old were used throughout the study.The endogenous cycle was found to take place in the small intestine where the parasites were located in the distal portion of the striated simple columnar epithelial cells of the villi. The first generation schizonts were found in only the jejunum (15% of small intestine). The second generation schizonts and gametes occurred in the jejunum and ileum (70% of small intestine), a slight posterior progression occurring with each stage. The entire cycle required 6.5 days.The schizogonous cycle comprised 2 generations. The first generation schizonts required 2.5 days to reach maturity, measured 8-12 μ, contained 16 merozoites measuring 12-15 μ and had a polar residual mass. The second generation schizonts required 2 days to reach maturity, measured 13-16 μ, contained 32 rotund merozoites measuring 6–8 μ, and had only a few granules of residual material.Gametogony took place in 1.5 days. The macrogametes measured 12-16 μ, and the microgametocytes measured 9-14 μ with microgametes measuring 5–6 μ.

Notes: SYNOPSIS. Trypanosomatid-free plants of the family Asclepiadaceae identified as Asclepias syriaca, A. curassavica, A. incarnata, Stephanotis floribunda, Seutera maritima, Amphistelma scoparia and plants of the family Euphorbiaceae identified as Euphorbia tirucalli, E. trigona, and Pedilanthus tithymaloides were exposed to the bite of the bug, Oncopeltus fasciatus, infected with Phytomonas elmassiani, a flagellate which occurs naturally in A. syriaca and O. fasciatus. Two weeks subsequent to exposure to laboratory-infected oncopeltids all the experimental Asclepiadaceae were infected. The mean length of the protozoa varied depending on the host plant. The flagellates in A. syriaca, A. curassavica, and A. incarnata were shorter than those in S. floribunda, S. maritima, and A. scoparia.None of the Euphorbiaceae became infected.

Notes: SYNOPSIS. The mechanism of Prymnesium parvum ichthyotoxicity was studied in immersed minnows (Gambusia affinis) in the presence of various synergists (especially polyamines and invert soaps) and under varying conditions of pH and salinity. The effect of immersion in toxin-synergist solution on permeability of gill tissues to trypan blue and to radioactive substances, e.g., I125 and radio-iodinated albumin, was established. Fish sensitivity to various toxic substances was increased after immersion for short periods in suitable toxinsynergist solutions. This sensitivity, as well as the increased permeability of gill tissue, was transient and disappeared when fish were stored in tap water for several hours after the toxin-synergist treatment. Good correlation was found between the conditions (synergist quality and concentration, pH, salinity) leading to P. parvum ichthyotoxicity and conditions instrumental in increased gill permeability and toxin sensitivity. The primary site of damage is concluded to be the gill membrane.

Notes: SYNOPSIS. Tetratrichomonas gallinarum was found in the blood of 3 chickens experimentally infected with Borrelia anserina. The blood infection was successfully reproduced in healthy chickens and was accompanied by evidence that the trichomonads multiplied in the blood, ingested red blood cells, and were themselves phagocytized by leucocytes. T. gallinarum was maintained in serial passage in chicken embryos as well as in the usual trichomonad culture media.

Notes: SYNOPSIS. Schwartz identified a protozoan, parasite of the marine fish Leiostomus xanthurus as a haplosporidian belonging to genus Ichthyosporidium Caullery and Mesnil, 1905. Now, a coiled polar filament in the spore of that organism has been clearly recognized in certain PAS preparations which were used in the original study. The parasite is, therefore, a microsporidian rather than a haplosporidian. The generic characters of this and other protozoans still in genus Ichthyosporidium need further study.

Notes: SYNOPSIS. Suspensions of whole, killed ciliates were diffused against rabbit antisera for the respective strains to observe cross precipitation. The strains fell into the following groups: I. GL, H, ChS, GP, Aq, L-I, L-II, L-2, and V1; II. W, L-3, Gl-R, and V2; III. PR and F; and IV. BF and Lava. T. vorax strains V1 and V2 each resembled certain T. pyriformis strains more closely than they resembled each other. The same grouping of strains emerged in comparing antigenic suspensions and in comparing antisera and was confirmed by comparing absorption properties of antigens from the different strains.

Notes: SYNOPSIS. Two hundred and fifty-nine specimens of the sea urchins Echinometra lucunter (201), Diadema antillarum (52), Tripneustes ventricosus (5) and Eucidaris tribuloides (1), collected on the littoral of the Federal District of Venezuela, were examined for intestinal ciliates.Iron hematoxylin and silver-impregnation staining technics permitted determination of eight of the nine ciliates found: Anophrys aglycus, A. elongata, Cohnilembus caeci, Biggaria bermudensis, B. echinometris, Cyclidium rhabdotectum, Metopus circumlabens and M. rotundus. An unidentified species of Euplotes was also found.

Notes: SYNOPSIS. The firm union of the shells of adult Gromia oviformis in plastogamous pairs is followed by gametogenesis and fertilization with the production of distinctive fusiform zygotes that undergo further transformation into amoebulae initially having hyaline radiate pseudopodia. The amoebulae emerge from the parental shells and probably initiate the asexual phase of the life cycle.

Notes: SYNOPSIS. The establishment of Eimeria acervulina sporozoites in the duodenal glands of Lieberkühn of the chicken is described. Sporozoites were found to enter the tips of the villi and pass into the lamina propria, or core, of the villus. Within the lamina propria, sporozoites were engulfed by macrophages and taken to the glandular epithelium.Data are presented which indicate that macrophages serve as a defense against infection as well as a mode of transportation.

Notes: SYNOPSIS. Electron microscope observations of a strain of Labyrinthula indicate that the spindle cells glide within a collapsible slime tube rather than on top of it. These slimeways are clearly extracellular, partly covered with membranes, and consist of an amorphous matrix encrusted with many small vesicular elements.

Notes: SYNOPSIS. Thirty-one stocks of a marine ciliate, Euplotes minuta Yocom, collected from different localities, can be grouped in seven mating types. True pairs are formed only in mixtures of stocks belonging to different mating types. No selfing pairs or intraclonal conjugation have ever been observed. Synclonal inheritance of mating types is the rule, although about 10% of pairs show clonal inheritance. The latter can be explained by assuming syncaryon formation through cytogamy or through caryogamy of pronuclei derived from different products of meiosis. Mating type determination is due to 7 alleles at the single locus mt. There is complete dominance among the 7 alleles which can be orderly seriated, as shown in Table 3, according to their dominance relationship. The 5 stocks, and only these 5, of mating type VII have the autogamy trait. The mortality rate in F1 and F2 is very low–a maximum of 10%; however, the F2'S obtained by autogamy from F1 progenies in which mating type VII is involved have a very high mortality rate. The two facts (high mortality rate in F2 and strict association of autogamy trait with mating type VII in natural populations) have been considered as evidences of a probable isolation mechanism existing between mating type VII and the other 6 mating types. Thus, the 7 mating types have been assigned to the same syngen only tentatively.

Notes: SYNOPSIS. Sporozoites of Lankesterella hylae were found in 12 of 13 green tree frogs (Hyla caerulea) from Gin Gin, Queensland. The intraerythrocytic sporozoites had two pale-staining vacuoles at the poles of the nucleus and frequently a dome-like protuberance on the concavity of the crescentic protozoon.Motility was observed in free but not intracellular sporozoites in fresh blood. Locomotion was of a gliding nature, though in addition parasites flexed and extended, and a peristaltic constriction passed backwards along the body of two. One parasite entered and emerged from a red cell, the erythrocyte playing a passive role.All stages of sporogony were observed in liver smears from a debilitated frog. In araldite sections of the small intestine of another frog, parasites were found in the vacuoles within unidentified cells in the lamina propria, thus suggesting that the parasite's point of entry is possibly the alimentary tract.

Notes: SYNOPSIS. Some of the serotypes in Paramecium caudatum are described in this paper. Immobilization antigens of P. caudatum have been obtained by extracting paramecia in a dilute salt solution containing 15% alcohol. Immobilization antigen F from stock 162 has been isolated and has a sedimentation coefficient of 9.3 Svedbergs, diffusion coefficient of 2.3 × 10-7 cm/sec, and molecular weight of approximately 340,000.

Notes: SYNOPSIS. Two species of Isospora are described from Chloris chloris with the additional hosts Passer domesticus and Fringilla coelebs. I. lacazei Labbé has spherical oocysts measuring 16.6 to 30.0 μ; the oocyst wall is colorless and smooth, consisting of a thick layer and, in the majority of oocysts, an inner thin membrane. Stages of the life cycle in the epithelial cells of the duodenum are described. The internal stages consist of first and late generation schizonts which produce merozoites without any residual body, spindle-shaped microgametes and macrogametes without obvious “plastic granules.” The oocysts of I. chloridis sp. n. have colorless, smooth surfaced walls of one thick layer. They are ellipsoidal, measuring 17.2-33.2 μ× 16.6-30.0 μ. The internal stages of this species infect the epithelial cells of the small intestine in the same region as I. lacazei. They produce 2 generations of schizonts, consisting of merozoites and a residuum; microgametes are comma-shaped and macrogametes have obvious “plastic granules.”

Notes: SYNOPSIS. Blood and tissue smears from 156 yellow-billed magpies showed infection with hematozoa in 154 (99%). Leucocytozoon berestneffi was found in 149 (96%), Haemoproteus picae in 40 (26%), Plasmodium relictum, in 32 (21%), Trypanosoma sp. in 3 (2%), and microfilariae in 42 (27%). Fifty-two birds were infected with two genera of parasites, 27 with 3, and 4 with 4. Leucocytozoon, Plasmodium and microfilariae showed a higher incidence in tissue than in blood smears.

Notes: SYNOPSIS. Monolayers of cells of coverslips were produced by culturing known numbers of trypsinized chick cells in growth medium (solution 199 plus 20% calf serum) at 37 C for 2 days. The fluid was then replaced with maintenance medium (solution 199 plus 5% calf serum) containing various known numbers of T. cruzi and the preparations were incubated at 33 C for 5 days; fresh maintenance medium was substituted on the 2nd or 3rd day. The inocula of parasites were obtained from T. cruzi-cell cultures, supplemented with 2% sterile NNN overlay, or from NNN cultures.The numbers of extracellular parasites, proportions of infected cells, and percentage distribution of infected cells relative to the number of intracellular leishmanial bodies were determined on days 2 or 3 and 5 of parasite cultivation in many experiments. Analyses of the data gave the following results. Extracellular parasites increased 2- to 14-fold during the first 2 or 3 days, depending upon the source and size of the inocula, and 10- to 20-fold during the last 2 or 3 days. Cell infection continued throughout incubation at daily rates of 1.4-4.5%; 8-22% of the cells became infected during the 5 days of incubation. Intracellular growth was reflected most clearly by increases in the proportion of cells having 〉10 leishmanial bodies. This increase was about 5% daily during the last 2 or 3 days of incubation.A useful test procedure for assessing the antiparasitic action and chick embryo cell toxicity of drugs is illustrated by data obtained with furazolidone and tris (p-aminophenyl)carbonium chloride.

Notes: SYNOPSIS. Tetrahymena pyriformis strains E, A-136 31C and IMT II survived freezing in 10% dimethylsulfoxide when the temperature was lowered to freezing at 4.5 C/min. Survival was then obtained for at least 128 days by lowering the temperature rapidly to 95°C. Of the 3 strains, T. pyriformis IMT II was most resistant to the effects of freezing. Its volume averaged about half that of either of the other strains and may have contributed to the differences in survival. In addition to differences among strains, a medium relatively low in the concentration of nutrients, a culture nearing peak population, and a rate of cooling of 4.5 C/min, all gave best survival. Paramecium aurelia regained motility after being frozen in 6 to 7.5% dimethylsulfoxide for as long as 7 days at either –27 or –196 C, but cultures were obtained only after storage for 20 min at –27 C. A concentration of 6 to 7.5% dimethyl-sulfoxide, cooling at 4.5 C/min, and culture media containing Aerobacter aerogenes or composed of a commercially available composition were all required for survival of P. aurelia.

Notes: SYNOPSIS. Silver impregnation techniques were used to study the silverline system of three species in the genus Spirostomum. It was concluded that for those species studied in the general area of Washington, D.C., the average numbers of ciliary meridians in S. teres, S. minus and S. ambiguum are 18, 24 and 46 respectively. Seventy-six % of the measurements in S. teres and S. ambiguum and 84% of the measurements in S. minus deviate from the mean by less than 1 standard deviation.

Notes: SYNOPSIS. Blepharisma seculum sp. nov. is described as a small-sized blepharisma with a compact, spheroid macronucleus and a distinct curvature of the body anteriorly. A comparison of this form with other species of the genus Blepharisma subgenus (Compactum) is given.

Notes: SYNOPSIS. Lymphotropha tribolii gen. nov., sp. nov. (Neogregarinida, Schizocystidae) is described from the haemocoele of Tribolium castaneum (Herbst) (Coleoptera, Tenebrionidae). The trophozoites are large, ovoid and uninucleate with distinct longitudinal striae. Schizogony occurs in one type of cycle only, each schizont giving rise to up to 8 merozoites. Gametocytes are uninucleate when they associate. Up to 16 oocysts each with 8 sporozoites are formed in each gametocyst. The oocysts are lemon-shaped, and sporozoites emerge from the poles.The parasite causes considerable mortality in young larvae, though its pathogenicity is probably inferior to that of Farinocystis tribolii Weiser.

Notes: SYNOPSIS. Sarcocystis garnhami n. sp. is described from an opossum, Didelphis marsupialis. Its distinguishing characters are the spiny cyst wall, 6–8 μ thick, and the size of the spores, 5.3–6.9 μ in length and 1.3–1.9 μ in breadth. Sarcocystis darlingi, Brumpt 1913 is considered Besnoitia darlingi (Brumpt, 1913) n. comb.

Notes: SYNOPSIS. An epizoic suctorian from Gulf of Maine coastal waters, designated as Paracineta sp., is described. Morphological measurements are given for 23 small, medium, and large specimens. Mean length was 200 μ and average cell body diameter 39 μ. Of 21 copepod species and 19 zooplankton groups examined, only copepods of the genus Metridia showed any Paracineta attached. Suctorian occurrence was, with a single exception, limited to adult copepods, with the larger females showing the heaviest incidence. Differences in areal occurrence were observed with greatest incidence of Paracineta on M. lucens in the eastern and central Gulf, and lowest numbers in the western area. This differential occurrence is accredited to an apparent cold water affinity of the suctorian. It is suggested that Paracineta could be carried into the Gulf during periodic intrusions of cool Nova Scotian water, reaching the western area in the southwesterly flowing Gulf of Maine eddy system. No significant differences in vertical distribution were found in Paracineta incidence on Metridia among the depths sampled (0, 10, 30, and 60 m). No harmful effect of Paracineta on Metridia was evident.

Notes: SYNOPSIS. The intralymphocytic stages of Theileria parva, T. lawrencei and T. annulata have been cultivated for several months in tissue cultures of bovine lymphocytes associated with baby hamster kidney cells. In established cultures the theilerial particles multiplied at about the same rate as the host cells, the percentage of infected cells and the mean number of parasite particles per cell remaining nearly constant.During mitotic division of the host cell the theilerial body becomes closely associated with the spindle fibres and is pulled apart and distributed to both daughter cells in late anaphase. The single theilerial particles (chromatin) within the theilerial body divide by binary fission; their division is not synchronous with that of the host cell.

Notes: SYNOPSIS. A sulfolipid, isolated from the phytoflagellate, Ochromonas danica, and from its medium, constitutes over 50% of the sulfur of the cells. It is bound to protein and excreted by the phytoflagellate. When the S35-labeled sulfolipid was placed in the medium it was incorporated by the cells without cleavage of the sulfate group. Thus it passes back and forth between the growth medium and the cells.The sulfolipid has been found in O. danica, O. malhamensis, Tetrahymena pyriformis, Chlamydomonas sp., Pseudomonas sp. (sea water bacterium). It was identified in the culture medium of O. danica, O. malhamensis, Chlorella pyrenoidosa, and Streptomyces griseus. Preliminary evidence was obtained for its presence in the growth medium of white clover and sorghum.

Notes: SYNOPSIS. The normal cycle of asexual reproduction in Euplotes eurystomus was subjected to a detailed morphological study using whole-mounted and sectioned material prepared by the method of silver impregnation. The cycle was arbitrarily divided into 7 stages (numbered 0–6) characterized by nuclear and cortical events. Particular attention was focused on the development of the oral primordium (OP), and the production of new kinetal cilia (or “dorsal bristles”).The OP is interpreted as originating from an invagination or infolding of the parental cortex, followed by considerable in situ growth and differentiation beneath the cell surface. It is suggested that differentiation beneath the parental cell surface may in some way facilitate morphogenesis of other cortical structures without necessitating dedifferentiation of the parent's buccal apparatus. During stage 6, the division constriction plays an important morphogenetic role in shaping the opisthe's buccal apparatus.During stage 4, a zone of ciliary increase (ZCI) appears in the central portion of each kinety. New kinetal cilia arise as semi-circular clusters of 1 to 9 kinetosomes flanking each old basal structure; the latter persist until the new organelles are well established. An analysis of total kinetal cilia in animals during stages 0 to 3 indicates that, while ciliary number varies according to animal size, there is no increase in cilia prior to formation of the ZCI.Several aspects of the asexual cycle in Euplotes seem to bear importantly on the more general problem of ciliate morphogenesis. The pattern or gradient concept might be useful in the analysis of factors determining primordial sites, although later development of the primordium into a specific organelle or organelle system is probably controlled by autonomous epigenetic processes that are somewhat independent of the parental cortical pattern. The hypothesis of kinetosome continuity cannot account for the origin of primordial fields in cortical regions remote from pre-existing kinetosomes, as observed in Euplotes. The initiation of morphogenetic activity on the cortex is closely correlated with, and may be causally related to, the appearance of replication bands in the macronucleus. The known metabolic significance of these bands, particularly the release of nuclear RNA, lends support to this suggestion.

Notes: SYNOPSIS. Experiments were performed to ascertain the effect of heat and cold on oral and micronuclear development in synchronized Tetrahymena pyriformis WH-6. The developing oral primordium becomes insensitive to cold sometime during stage 2. Cold shocks cause the reversion of many stage 2 primordia to stage 1. Cells so affected are set back in division. The delayed division is always asynchronous. When heat shocks are applied prior to late stage 4, the developing primordium will regress. High temperature shocks applied at later stages permit continued development. However, when the cell begins to cleave at the high temperature, division is frequently arrested and the new oral areas regress. Subsequent cell separation is greatly delayed and asynchronous.Heat and cold affect the micronucleus in the same way. Both agents prolong the arrest of mitosis brought about by the synchronizing treatment. A temperature shock is ineffective if applied after there is a space completely separating the chromosome groups, so that mitosis is completed in the presence of the agent. Bimicronucleate chains result in those cases in which division is arrested by heat shocks.It is suggested that the different phases of sensitivity to heat and cold may reflect different types of syntheses necessary for development of the oral primordium. Division arrest and subsequent oral replacement might possibly be related to high temperature induced changes in the physical state of the ciliate cortex.

Notes: SYNOPSIS. The free amino acids of E. invadens and 4 strains of E. histolytica cultured in the CLG medium have been identified by thin layer chromatography. The chromatogram patterns of 3 strains grown for 72 hr at 37°C (103, K-9 and 200) were nearly identical. Amino acids detected on chromatograms according to Rf values, relative positions on chromatogram plates, and identifying colors using a polychromatic ninhydrin spray were: leucine/isoleucine, tyrosine, valine, alanine, glycine, glutamic acid, lysine/ornithine, histidine, proline, plus very small amounts of arginine and possibly serine, aspartic acid and citrulline/glutamine. Cysteic acid may also be present. The same amino acids were detected on chromatograms using comparable extracts of strain Laredo and E. invadens grown for 6 days at room temperature. However, the patterns were different in that serine, glycine, threonine and especially alanine were present in greater abundance in these latter 2 cell types.These chromatogram patterns were compared with similar analyses of strains Laredo and 200 grown in the modified Shaffer-Frye medium of Reeves.Similar analyses are reported on the basic ingredients of the CLG medium, including the cells and protoplasts of the Bacteroides, the non-multiplying bacterial associate employed in the CLG medium. The chromatogram patterns of the Bacteroides, protoplasts and medium were decidedly different from those of the amebae, thus indicating that adequate separation of bacteria, amebae and medium was accomplished.Analyses of the culture filtrates of all cells analyzed revealed a possible difference between the Laredo strain and the other strains of E. histolytica (103, K-9 and 200) in amino acid utilization. Similar differences were observed between the Laredo strain and E. invadens.

Notes: SYNOPSIS. Colligocineta furax gen. nov., sp. nov., parasitizes the epithelial cells of the peristomial cirri of the sabellid polychaete Laonome kröyeri Malmgren. The material studied was dredged in West Sound of Orcas Island, San Juan Archipelago, Washington. In general, the pattern of ciliation of Colligocineta resembles that of Hypocomella and Heterocinetopsis. However, of the ten kineties which constitute the ciliary system, two from the extreme right side appear to be continuous with two from the left side. During division, the posterior part of the ciliary field is conferred upon the opisthe, and in the proter all of the ten kineties are for a time completely separate.

Notes: SYNOPSIS. Myxosoma cartilaginis n. sp. is described from the cartilage of Lepomis macrochirus (bluegill), L. cyanellus (green sunfish) and Micropterus salmoides (largemouth black bass). The development of the parasite is described from naturally infected fish which were held in spore-free water after infection. The sporoplasm invades cartilage, and becomes a multi-nucleate trophozoite which forms pansporoblasts, each of which produces 2 to 4 spores. The first spores appear in 7 weeks.The histopathology in the above fish consists at first of little cellular reaction, but after 4 to 5 months epithelioid granulomas appear around some of the spore masses. Cartilage liquefaction is present around the parasites for at least 5 weeks. Eosinophilic globules are present in cartilage cells adjacent to the lesions. Diffuse infiltration of the spores from the lesions is described.Of 24 chemicals tested for polar filament extrusion, potassium hydroxide gave the best results.An illustrated synopsis of the Myxosoma of North American fishes is given. Included is some additional information and illustrations of M. hoffmani Meglitsch, 1963. Also included is a table showing the hosts, site of infection, geographic location, spore and polar capsule sizes.

Notes: SYNOPSIS. Two species of hysterocinetids occur in the alimentary tract of Drilocrius breymanni, an aquatic oligochaete collected in Departamento del Valle, Colombia. The suckers of both species are unusual for their complexity. In Craticuloscuta escobari gen. nov., sp. nov., the sucker is a shallow oval concavity with longitudinal and transverse supporting elements. About one-fifth of the area of the sucker, in its posterior portion, is ciliated, but argyrophilic punctations, which probably represent kinetosomes, are distributed in a regular pattern over most of its surface. In Epicharocotyle kyburzi gen. nov., sp. nov., the oval major portion of the sucker is deep, and continuous with a short trough which extends posteriorly and bends toward the left. Veil-like flanges, bordered by a fringe of thick, inactive cilia, arise from the margins of the sucker on either side. In the region of the trough, the flanges may overlap in such a way that the trough is almost completely covered. The trough and a small area of the major portion of the sucker anterior to it are ciliated. However, argyrophilic punctations which probably represent kinetosomes are distributed over most of the surface of the sucker. The pattern of longitudinal and transverse supporting elements found in the sucker itself extends into the flanges. In both Craticuloscuta and Epicharocotyle, the arrangement of the adoral and buccal ciliary organelles is essentially like that in Hysterocineta, Ptychostomum, and other ciliates of the family Hysterocinetidae.

Notes: SYNOPSIS. Various protozoa and lower metazoa were exposed to filtrates of Staphylococcus aureus B (formerly called Type S-6) (2) and non-enterotoxigenic filtrates of staphylococci to study the toxicity of staphylococcal enterotoxin to these organisms. No reaction specific for enterotoxin was observed either in those culture filtrates from toxin-producing strains or in solutions of purified enterotoxin. Non-specific reactions were obtained with various growth media and a “potassium inhibited” filtrate containing 0.5% K2HPO4.

Notes: SYNOPSIS. The effect of hexamethonium chloride, an acetyl-choline competitor, on the ciliary and myonemal systems of Spirostomum intermedium and S. ambiguum was investigated. Although the drug caused immobilization of the cilia, severe cell damage often ensued indicating an unspecific action. The general reaction was usually more severe and the ciliary inhibition less in S. ambiguum than in S. intermedium. It is postulated that the general reaction is the result of either membrane depolarization or binding of hexamethonium at the surface. Fed animals were more susceptible to drug action than starved ones. Raising the external potassium level did not affect the drug action.

Notes: SYNOPSIS. A morphological study on the ectoplasm and the proboscis in the ciliate Didinium nasutum, has been performed by means of an electron microscope. The ectoplasm and the endoplasm of Didinium are separated by a fibrous layer. In addition to the ciliary apparatus and the filament system, the ectoplasm is characterized by having ectoplasmic vacuoles enclosing cross-striated bodies and by having small rods surrounding the ciliary basal body.The filament system is composed of 4 types of tubular filaments: primary filaments originating from the basal body, secondary ones coursing longitudinally along the cell periphery, tertiary ones going down in cylindrical arrays from the periphery of the proboscis into the endoplasm, and finally kinetosomal ones from the base of the basal body into the endoplasm through the newly found pore of the fibrous layer.The fine morphology of the trichites in the proboscis is elucidated three-dimensionally and illustrated schematically. Moreover, the correlation among the small rod, ectoplasmic vacuole and trichite is discussed.

Notes: SYNOPSIS. Animals arising spontaneously in a culture of Paramecium aurelia, variety 4, strain 51.8s, swam about three times as rapidly as normal 51.8s, 51.7s or 29.8 animals. When the 51-fast animals were mixed with 51.8 or 29.8 paramecia, a random sampling of swimming rates showed a bimodal distribution. The faster rate of 51-fast animals was maintained under such deleterious conditions as 48-hour starvation. “Fastness” or “slowness” could not be selected for in vegetative clones. The 51-fast paramecia would not mate with 51.7, 51.8 or 29.8 animals, although fission rate, serotype and general appearance indicated that 51-fast probably arose from strain 51.8.

Notes: SYNOPSIS. Silver stains of the free-swimming sessiline peritrich Opisthonecta henneguyi reveal the adoral infraciliature as the bases of two membranes, a haplokinety and a polykinety, which diverge at the buccal overture and spiral down the infundibulum to end at the cytostome. A second polykinety parallels the adoral polykinety in the oral half of the infundibulum, and the two form a peniculus. The haplokinety appears as a single row of kinetosomes, the adoral polykinety as a series of transverse rows of three kinetosomes. The peniculus is six kinetosomes in width.The electron microscope shows that the haplokinety is a double row of staggered kinetosomes. Only the external row bears cilia. The polykinety is a complex ciliary membrane, three kinetosomes wide. The three kinetosomes are connected with one another by fibrous bundles passing beneath them. They are linked orally and apically into longitudinal rows of thick, zig-zag, fibrous connections. The kinetosomes of the internal longitudinal row are attached by a dense fiber to a strand of fibrous material interrupted at regular intervals by dense nodes.A section of the wall of the infundibulum is thrown up into longitudinal folds with tubular fibrils running parallel to the folds. These structures, the crests, appear to continue into the cytopharynx. Beneath and around the adoral and infundibular infraciliature and the crests is a fibrous matrix with dense nodes, resembling the reticulated infundibular fiber described by Faureé-Fremiet.The trochal band in silver stains appears as short diagonal rows of kinetosomes. The electron microscope shows 5 to 7 kinetosomes per diagonal row. The kinetosomes of the diagonal rows are linked to thick dense rods which originate just above the trochal band and continue antapically past the kinetosomes for a distance of 10 to 15 μ. The kinetosomes are joined to one another by fibrous strands and each is also connected by a dense fiber to the diagonal rod to its left. Running below the kinetosomes and at right angles to the rods is a system of striated fibers.At the aboral end of the body, a ring, 2 μ in diameter, of argentophilic granules is shown by the electron microscope to be a small circle of kinetosomes. Sessile stages have not been reported for Opisthonecta. The aboral ring is probably a vestigial or non-functioning scopula.The argyrome is represented by circular striae around the body. Each stria bears argentophilic dots on either its apical or its antapical side. Electron microscopy reveals that these dots are pores in the cuticle. The striae themselves may be points of adhesion between the inner cuticle and the outer cuticle, or ridges of cytoplasm between flattened alveoli of the inner cuticle. A dense fiber runs below and parallel to each stria. Opisthonecta shows at least three different kinds of ciliary membranes. Some speculations are offered on the taxonomic affinities of peritrichs based on their infraciliature.

Notes: SYNOPSIS. Haplosporidium mytilovum Field, 1924, a sporozoan (?) parasite in the ova of the mussel Mytilus edulis L., is found to be morphologically similar to, and deemed to be congeneric with, the type species of genus Chytridiopsis Schneider, C. socius S., 1884, in beetles. It is compared also with the only other reported species of Chytridiopsis in a mollusc, C. ovicola Léger and Hollande, 1917, in ova of the European oyster, Ostrea edulis L. These two parasites in ova of bivalve molluscs are much alike but, since they seem to have some slight morphological differences, it would be premature to conclude that they belong to the same species. Chytridiopsis, a genus of uncertain affinities, has been considered by various authors to be related to the Chytridiales, the Haplosporida, the Mycetozoa or the Microsporida. New evidence favors the hypothesis that it is microsporidian in nature, although proof in the form of a clearly demonstrated polar filament has not yet been produced.

Notes: SYNOPSIS. Leptomonas costoris n. sp. is described from Gerris comatus. It differs from other species of Leptomonas in the structure of the reservoir which has ultramicroscopic thickenings in its wall, matched by corresponding thickenings in the adjacent flagellar membrane. The one or two diagonal lines seen in the reservoirs of Giemsa-stained specimens are thought to be manifestations of these ultramicroscopic fibrils. The reservoir structure suggests a close relationship between this species and Cryptobia, (family Bodonidae) in which somewhat similar structures have been described. Blastocrithidia veliae is redescribed and differentiated from B. gerridis.

Notes: SYNOPSIS. Glucose-6-phosphate dehydrogenase activity and the level of reduced glutathione were assayed in host-parasite interactions in which the malaria parasites preferentially invade: 1. mature erythrocytes (Plasmodium lophurae in the duck) and 2. reticulocytes (P. berghei in the mouse). Assay for glucose-6-phosphate dehydrogenase was by the dye decolorization test of Motulsky and Campbell. In P. berghei infected mouse erythrocytes with parasitemias ranging from 28–78% there was no deficiency in enzyme except at the 78% level. Similarly, P. lophurae-infected duck erythrocytes with parasitemias of 29–114% showed no enzyme deficiency except above the 80% level. No linear relationship existed between parasitemia and enzyme level. The reduced glutathione stability test of Beutler in duck erythrocytes infected with P. lophurae in the range 27–67% showed no glutathione instability.

Notes: SYNOPSIS. Axenic cultures of Tetrahymena pyriformis W were used to obtain fractions rich in kinetosomes by alcoholdigitonin extraction techniques followed by centrifugation. The morphology of the kinetosomes was examined in the electron microscope at various stages during the isolation procedure, and compared to the morphology of the in situ kinetosome. In the latter preparation the well known cartwheel structure was present, and in addition 9 electron dense dots were displayed at the end of each spoke of the cartwheel.The prepared kinetosomes could easily be identified during the entire process, and there was no apparent change until after the digitonin step. However, with the further fractionation, alteration was found to have taken place in the interior and in the kinetosome wall. The inside appeared “empty,” and we were not able to find 9 triplets in the wall but only doublets.In view of the morphological alterations in the kinetosomerich fractions, chemical analysis still appears to us to be premature.

Notes: SYNOPSIS. Excystment of Didinium nasutum is solely dependent upon dense bacterial populations and is independent of the type of medium in which the bacteria have been grown. Beers' hypothesis of the need for a factor from proteose-peptone is thereby not confirmed, but the need for living, intact bacteria as postulated by him is fully shown. The process of excystment is initiated by bacteria, but their presence is not required throughout the excystment. Axenically grown paramecia, shown to be adequate as food organisms for didinia, will not induce excystment. Five types of bacteria including Gram-positive, Gram-negative, aerobic and anaerobic all suffice to induce excystment, suggesting that the initiation of this process is caused by some general metabolic process or product of bacteria.

Notes: SYNOPSIS. About 50% of the amoebae found in early prophase through metaphase stages of mitosis have at least some mitochondria (ca. 25%) that contain complex internal structural patterns. These patterns are less frequently seen in mitochondria after metaphase, and they are extremely rare or absent during interphase. In the most typical pattern, larger than normal tubules are arranged in a parallel zig-zag configuration with a small amount of matrix between them. Complex patterns typically comprise about 30% of the mitochondrion; they are usually confined to one area, the remaining portion consisting of a clear matrix with few, if any, peripheral tubules.

Notes: SYNOPSIS. Examination of feces obtained from wild-trapped woodchucks, Marmota monax, near Chambersburg, Pennsylvania, revealed three previously described species: Eimeria monacis, E. perforoides, and E. os. In addition I found a new coccidium, E. tuscarorensis n. sp., described in this paper. Structurally the new species resembles E. wisconsinensis and E. bilamellata. An unidentified polysporocystic coccidium, possibly the genus Klossia, was found in small numbers in one sample.

Notes: SYNOPSIS. Laboratory cultures of the boll weevil, Anthonomus grandis Boheman, became infected with Mattesia grandis n. sp. (Neogregarinida, Ophryocystidae). The ensuing epizootic resulted in destruction of the weevil colony. Infection occurred per os in larval and adult weevils. Sporozoites penetrate the intestinal wall and infect adipose tissue cells. Micronuclear schizogony with production of merozoites is the primary method of multiplication and spread to new foci. Micronuclear schizonts may grow as large as 30 μ in size and produce up to 200 or so merozoites, which may be 20 μ long and 1–2.5 μ wide and are motile. Macronuclear schizonts are formed from these 1st schizogony merozoites, and can become 20–30 μ in size, producing up to 80 or so macronuclear merozoites. These can be 15 μ long but 2–3 μ wide with limited motility. Second schizogony merozoites form gamonts, which pair, forming gametocysts. Nuclear division occurs, resulting in 4 equal sized nuclei and 2 pairs of residual nuclei. Four gametes are formed by cytoplasmic constriction around the nuclei. The gametes rapidly pair to form 2 zygotes in the gametocyst, resulting in 2 spores. Nuclear pairing in 1 of the 2 zygotes often lags slightly behind. Abnormal development of zygotes was rare, but could result in 1 spore with 3 poles and a normal spore, or with only 1 spore developing. Near maturity gametocysts are about 12.5 μ long and 14.0 μ wide, with the gametocyst wall tightly stretched over the poles of the spores. Spores often are slightly flattened on the adjacent side in the gametocyst but frequently attained evenly curved walls on all sides after release. The spores are octozoic, with sporozoite development occurring after release from the gametocyst. Spores measured 7.1 μ X 11.8 μ. Characters are given to separate M. grandis from other species of Mattesia.

Notes: SYNOPSIS. Broad scope investigations have allowed a study of the intestinal parasitic protozoa of the Kenya baboon Papio doguera in its natural habitat as well as an opportunity to follow the intestinal protozoan populations in these primates held in captivity. Samplings indicate that the amoebae found in the baboon are essentially the same as those which commonly occur in man. Balantidium coli is frequent in wild baboons but is self-limiting in animals after a few weeks in captivity. The flagellates Chilomastix mesnili and Giardia lamblia were detected in captive but not in wild baboons; the presence of the latter constitutes a new record for Papio doguera.

Notes: SYNOPSIS. Experimental observation of the pathogenicity of some strains of Hartmannella plus the observation of human meningo-encephalitis due to small amebas which had a structure compatible with that of Hartmannella in the tissues has suggested the concept of respiratory amebiasis followed by cerebral and other complications.Until recently no cultural evidence was available to identify positively the amebas in the human cases. This report summarizes the isolation of Naegleria sp. (HB-1) from human spinal fluid by mouse inoculation followed by tissue culture of the infected mouse brain. C. Butt and his associates, who submitted this material to us, isolated the Naegleria on agar medium with Escherichia coli without antibiotics at 37 C.The new isolate failed to grow on the medium previously suggested by us for Hartmannella. HB-1 is virulent for laboratory animals and has a structure in the tissues which more resembles the amebas in the human tissue than the amebas in experimental Hartmannella infections of mice. Naegleria and Hartmannella are both potential pathogens for normal animals and man. A clinical laboratory method to detect Naegleria as well as Hartmannella is herein suggested.

Notes: SYNOPSIS. Reticulocytosis, stimulated by the destruction of red blood cells by phenylhydrazine, altered the course of infection of both Plasmodium chabaudi and P. berghei in the mouse. P. chabaudi, lacking a preference for reticulocytes, was adversely affected when young cells were present in abundance. Parasitemias diminished and most of the animals survived the otherwise fatal infection. P. berghei preferentially invaded reticulocytes to the extent that the parasitemia became contained largely in the reticulocyte population. This was accompanied by a delay in time to death.

Notes: SYNOPSIS. Uronema nigricans, a hymenostome ciliate, is redescribed by modern technics. Anatomic studies were made on 4 strains treated primarily with the Chatton-Lwoff silver impregnation technic. Particular attention was given to the buccal apparatus and its importance to generic assignment in the order Hymenostomatida.

Notes: SYNOPSIS. A hyperparasite probably related to some lower protistan was found in the cytoplasm of Entamoeba suis Hartmann. These were very minute bodies with a central Feulgen-positive dot, the nucleus, and a bordering cytoplasmic ring with an alcian blue-positive reaction. This organism appeared to interfere with the synthesis of DNA & RNA in the host amoeba as reflected in its relative stainability with Feulgen or pyronin-methyl green. The suggestion is that the parasitized amoebic cysts were most likely rendered nonviable.

Notes: SYNOPSIS. Cell-free preparations from Crithidia jasciculata carried out protein synthesis as measured by 14C-leucine uptake (optimum ∼ 10 mM Mg++) and poly U-directed 14C-phenylalanine uptake (optimum ∼ 16 mM Mg++). Characteristics of the system and sucrose density-gradient patterns of ribosomes were investigated. The charging and transfer reactions—the 2 main steps in protein synthesis—were inhibited by stilbamidine, hydroxystilbamidine, pentamidine, quinapyramine (Antrycide), and suramin.

Notes: SYNOPSIS. Cohnilembus verminus, a marine hymenostome ciliate, is described from a culture taken at Eniwetok. Anatomic studies were made on specimens treated primarily with the Chatton-Lwoff silver impregnation technic.

Notes: SYNOPSIS. Eimeria callospermophili was found in 6 species of ground squirrels and the white-tailed prairie dog. The hosts included Spermophilus armatus from Utah and Montana, S. richardsoni from Montana and Wyoming, S. beecheyi from California, S. lateralis and S. variegatus from Utah, and S. tridecemlineatus and Cynomys leucurus from Wyoming. Infections were generally transmissible from each species of ground squirrel to S. armatus and S. richardsoni. Oocysts from C. leucurus caused infections in S. armatus and S. richardsoni. No infections were found after inoculation of E. callospermophili oocysts into least chipmunks (Eutamius minimus), Mongolian gerbils (Meriones unguiculatus), or laboratory rats; however, excystation occurred in these animals. Resistance to infection did not develop in S. armatus, S. richardsoni, or S. variegatus, but did occur after 5 or more infections in S. lateralis. Eimeria callospermophili had little or no effect on the host in S. armatus, S. lateralis, or S. variegatus, but caused bloody diarrhea in severely infected individuals of S. richardsoni.The oocysts had an oocyst residuum consisting of several distinct bodies, which later coalesced to form a large homogeneous body. Each sporozoite had an unusually large refractile body. In experimentally infected specimens of S. armatus the prepatent period and patent period lasted for 5 and 9 days, respectively. Mature 1st-generation schizonts, first seen 2 days after inoculation, had 8–12 merozoites. Mature 2nd-generation schizonts, first seen 3 days after inoculation, had an average of 18 merozoites which were smaller than those of the 1st generation. Mature gametes were 1st seen 4 days after inoculation. Mature microgametocytes were only slightly larger than mature macrogametes.

Notes: SYNOPSIS. The conclusion drawn in 1921 that the large nuclei in the cytoplasmic cortex of Glugea cysts are not vegetative nuclei of the microsporidan but nuclei of the hypertrophied host cell was based on the discovery of early developmental stages in the mesenchyme of stickleback larvae experimentally fed Glugea spores. This observation had been made on serial sections from experiments done in 1912. The intracellular development of the microsporidan could be followed up in this material only thru the 1st stages of schizogony. Renewed infection experiments, done still in 1921 on a much broader basis, have fully confirmed the previous findings, as briefly stated in 1922. On this material, the intracellular development of G. anomala has been followed up in recent years from uninucleate host cells 7 μ in diameter, interpreted as wandering cells in the mesenchyme, until they became macroscopic multinucleate cysts, in which schizogony and sporogony of the microsporidan produced innumerable vegetative stages and spores of Glugea. The details of the developmental processes are described in the present paper.The multinucleate host cell and the intracellular parasites together form one of the symbiotic complexes for which the term “xenom” or “xenoma” has been used by me since 1949. By a sequence of amitotic nuclear divisions, the uninucleate host cell in the Glugea xenomas of Gasterosteus becomes plurinucleate in contrast to the usual structure of other xenomas of fish.Already in 1921, I thought that the host cell in the Glugea xenomas may have phagocytic properties. The observation of accumulation of granules from pigment cells in some of the Glugea xenomas has now verified this supposition.

Notes: SYNOPSIS. Eimeria eumopos n. sp. (Coccidiida, Eimeriidae) from a Colombian bat Eumops trumbulli (Chiroptera, Molossidae) is described. This is the first recorded coccidium in a bat from the western hemisphere, and the sixth bat coccidium species described to date. The unsporulated oocysts in the bat feces are 30.9–24.0 by 28.9–23.2 μ (near 28.8 × 26.1 μ). Their outstanding feature is the pronounced pitting of the thick brownish oocyst wall.

Notes: SYNOPSIS. An electron microscope study of Plasmodium coatneyi in the rhesus monkey supplied information on the fine structure of trophozoites, gametocytes and of the host cell. The trophozoites resemble other mammalian malaria parasites. They do not have typical protozoan mitochondria, but instead a concentric double-membraned organelle, which, it is assumed, performs mitochondrial functions. They feed on the host cell by pinocytosis, engulfing droplets of erythrocytes thru invaginations of the plasma membranes at any region of the cell or thru the cytostome. Digestion of hemoglobin takes place in small vesicles pinched off from the food vacuole proper.Gametocytes can be clearly distinguished into macro- and microgametocytes. Macrogametocytes are covered by 2 plasma membranes, the inner one appearing thicker in some places. The cytoplasm is filled with Palade's particles and has numerous vesicles of endoplasmic reticulum and toxonemes. In microgametocytes most of the inner membrane is thickened, the cytoplasm has few Palade's particles and vesicles of the endoplasmic reticulum and does not have toxonemes.Erythrocytes with trophozoites are irregularly scallop-shaped and have elevated points with knob-like protrusions covered by a double membrane. If these protrusions are sticky they might be in part responsible for clumping and arresting the schizonts and segmenters in the capillaries. The host cell contains numerous Maurer's clefts which in some instances are continuous with the membranes of the parasite suggesting that they might originate from them.

Notes: SYNOPSIS. Mice, segregated in groups according to sex and age from 5 to 21 weeks, and randomly presented, were inoculated in one continuous process with a trypanosome suspension prepared from a Trypanosoma brucei subgroup stabilate of such a dilution that about 50% of the mice might be expected to become infected. No statistically significant difference occurred between groups, either with regard to sex or to age.Significant alterations in the proportions of mice infected did, however, occur in relation to inoculation order. The inoculation process occupied 12–197 minutes after removal of the stabilate from −79 C storage. Essentially, infectivity rose initially to a peak between 30 and 80 minutes, and then fell off, but was not abolished at the end of the experiment.

Notes: SYNOPSIS. Observations were made on the fine structure of Paramecium bursaria and its intracellular Chlorella symbionts. Emphasis was placed on the structure of the algae and structural aspects of the relationship between the organisms.The algae are surrounded by a prominent cell wall and contain a cup-shaped chloroplast which lies just beneath the plasma membrane. Within the cavity formed by the chloroplast are a large nucleus, a mitochondrion, one or more dictyosomes, and numerous ribosomes. The chloroplast itself is made up of a series of lamellar stacks each containing 2–6 or more thylakoids with a granular stroma and starch grains intercalated between the stacks. The thylakoid stacks of mature algae are frequently more compact than those of recently divided algae. A large pyrenoid is located within the base of the chloroplast. It is made up of a granular or fibrillar matrix surrounded by a shell of starch. The matrix is bisected by a stack of 2 thylakoids. Prior to the division of the chloroplast the pyrenoid regresses; pyrenoids subsequently form in the daughter chloroplasts thru condensation of the matrix material and the reappearance of a starch shell. This shell appears to be formed by the hollowing-out of starch grains already present in the chloroplast stroma. Accordingly, in this case, starch moves from the stroma to the pyrenoid.The algae are located thruout the peripheral cytoplasm of the Paramecium. Each alga is located in an individual vacuole except immediately following division of the algae when the daughter cells are temporarily located in the vacuole which harbored the parental cell. Shortly thereafter the vacuole membrane invaginates, thereby isolating the daughter algae into individual vacuoles. Degenerating symbiotic algae are seen; because these are frequently found in vacuoles with bacteria, they are presumed to be undergoing digestion. Due to the conditions of culture these algae could have been either of intracellular or extracellular origin.

Notes: SYNOPSIS. Electron-microscopic observations were performed on 2 species of Volvox, one similar to V. globator, the other to V. aureus. The former has distinct protoplasmic connections in the adult coenobium and specific structures, named “medial bodies,” in the connections just at the intersection with the middle lamella. The medial body is disk shaped, about 800 mμ in diameter, and is composed of 3 parts, 2 dense outer layers and an intermediate less dense zone. In the latter species, the connection and medial body were not seen. On the other hand, it was commonly seen in both of them that in younger, dividing gonidia neighboring protoplasts were connected with each other by protoplasmic bridges. The bridges are undoubtedly formed due to incomplete cell separation in the division of a gonidium. The structural difference in the adult coen***bium between the 2 species emerges just after inversion of the coenobium. In the globator type the medial body appears just after inversion, and the connection remains unruptured all thru life. In the aureus type, it seems that the connections are withdrawn or degenerate immediately after inversion. It is discussed whether protoplasmic continuity is really maintained by the connection or not in the freeswimming coenobium of Volvox.

Notes: SYNOPSIS. Plasmodium lophurae hemozoin (malaria pigment) is a heme-containing protein which is distinctly different from hemoglobin and hematin by immunologic, spectrophotometric, fingerprint, heme-iron, gel filtration, and starch gel electrophoretic analyses. The calculated average molecular weight of P. lophurae hemozoin is ca. 40,000. Hemozoin contains at least 3 antigenic components and shows some indication of cross-reaction with hemoglobin.

Notes: SYNOPSIS. In tryptone media, optimal growth of nonphotosynthetic Euglena gracilis var. bacillaris on glucose occurred with 1% (w/v) glucose at pH 3.5, and required a previous adaptive period in glucose medium.In short term metabolic experiments, glucose uptake was greatly stimulated by small concentrations of tryptone or succinate; effects of shaking suggested that CO2 has a similar stimulatory effect. Glucose utilization was highly dependent on glucose concentration, with an apparent threshold at about 2 mM and increasing steeply with glucose concentration above this value. In tracer experiments, about 90% of the glucose carbon consumed was assimilated, and about 10% released as CO2.Glucose did not stimulate respiration even during rapid glucose utilization. Tracer studies indicated oxidation of endogenous substrates was depressed by an amount which just compensated for the respiration due to glucose.The conditions which allowed rapid glucose utilization by “resting”E. gracilis var. bacillaris were the same as those known previously to be required for growth on glucose. It was therefore concluded that these factors act directly on the main pathways of glucose metabolism.

Notes: SYNOPSIS. Microstome →macrostome transformation in Tetrahymena vorax was induced by suspending microstomes in a transforming principle, stomatin, released by a potential prey, T. pyriformis. It was found that 70–90% of the microstomes formed macrostomes within 7 hours following suspension in this transforming principle. Macrostome formation occurred by the process of oral replacement. This process involved resorption of the microstome oral apparatus and its replacement with a larger (macrostome) one, which arose from an anarchic field that formed behind the resorbing oral area. Ninety-five percent of those microstomes which were destined to form macrostomes were in some stage of oral replacement 195 minutes after their suspension in stomatin. Several commercially produced products were tested over a wide range of concentrations to determine their ability to act as an inducer of macrostomes. Only 2, Trypticase and Bactocasitone, had any activity, and it was too small to be considered really effective. An attempt was also made to destroy the activity of stomatin by using enzymes. RNAse was effective but only in very high concentrations, so it was suggested that this activity might be related to the destruction of RNA within the transforming cell and not related to hydrolysis of stomatin. None of the other enzymes tested had any effect in reducing the activity of stomatin.

Notes: SYNOPSIS. A developmental sequence is proposed for the haplosporidan Minchinia nelsoni Haskin, Stauber and Mackin, 1966, based on study of oyster infections over the past 5 years in Chesapeake Bay. Uninucleate stages develop by nuclear division into multinucleate plasmodia which proliferate in the tissues by plasmotomy. Relatively small plasmodia containing what are considered to be gametic nuclei originate by unequal plasmotomy of large plasmodia. These have been interpreted to aggregate and fuse to form large plasmodia which contain prozygotes. Pairing and fusion of nuclei occur within each plasmodium to produce zygote nuclei (synkaryons) which undergo division, possibly meiotic, to form sporonts. Sporoblasts differentiate into spores with the development of spore walls and opercula. Cystoid plasmodia develop during times of unfavorable conditions. An anomalous but common sequence involving sexuality and mitosis is described, and the occurrence of various life cycle stages within the host thruout the year is discussed.

Notes: SYNOPSIS. Many of the sub-pellicular and infraciliary structures in protozoa have proved difficult to study with standard thin-sectioning technics. When these structures are viewed in isolated and fragmented form, many of the thin-sectioning difficulties are circumvented. Langmuir-trough isolation followed by critical-point drying, as well as thin sectioning, were used in this study to determine the patterns of sub-pellicular microtubules and fibrils interconnecting kinetosomes of membranelles and cirri of Euplotes eurystomus. The fibrillar network in the bases of these ciliary organelles is presented in some detail and apparent variations in pattern are noted. Functional aspects of some of the structures are discussed. With special preparation nearly whole Euplotes may be obtained for study in the electron microscope. Fused cilia were frequently obtained and their ultrastructure was studied.

Notes: SYNOPSIS. A technic is described for the quantitative assay of paramylum content of euglenoid flagellates. The method relies on the alkaline solubility of paramylum followed by treatment with the anthrone reagent. The intensity of the color developed by paramylum is about 14% greater than that developed by an equivalent amount of glucose. The method is sensitive down to about 10 μg.

Notes: SYNOPSIS. The development of three 8-liter and four 12-liter cultures of the photosynthetic dinoflagellate Gonyaulax monilata was followed for 4 months. Weekly estimates were made of population levels of this chain-forming flagellate, along with incidence of cells in chains and toxicity to fish. Guppies (Lebistes reticulatus) were used to assay toxicity. Populations reached a peak when cultures were 3–5 weeks old, declined during weeks 6–10, and tended to stabilize thereafter thru the 17th (final week). The percentage of cells in chains was related to the slope of the population curve; rapidly increasing populations had the highest proportion of long chains, suggesting that incidence of chains is an index of the growth phase in G. monilata. Peak toxicity was not reached until culture populations had been steadily declining for a month, indicating that most toxin is released by autolysis. The reproducibility of culture population and toxicity levels recommend the methods used for future studies.

Notes: SYNOPSIS. The pigments synthesized by Astasia ocellata include α- and ε-carotene, 4-keto-β-carotene (echinenone), and 4,4′-diketo-β-carotene (canthaxanthin); 4-keto-α-carotene, accounting for about half the pigment in the cells, was tentatively identified; a strongly adsorbed keto-carotenoid, accounting for 25% of the pigments and bearing some similarities to astacin, polytomaxanthin and phoenicoxanthin, was also found.

Notes: SYNOPSIS. Blepharisma intermedium was cultured axenically. The organisms were freed of contaminating microorganisms by serial washing in a sterile salt solution. The major nutrients in the various media were: Freshly killed or lyophilized and autoclaved bacteria (Pseudomonas ovalis), yeast extract prepared from Fleischmann's baking yeast or Fleischmann's yeast autolysate, lettuce infusion or stigmasterol, 6 B-vitamins, and phosphate buffer at 2 times 10−3 M. The cultures were kept in the dark at 25 C. Altho the 1st division after transfer into fresh media was delayed, B. intermedium divided in approximately 32 hours thereafter in most of these media.

Notes: SYNOPSIS. The effects of temperatures of 12–18 C on cell division and oral primordium development were investigated in cultures of synchronized Tetrahymena pyriformis GL-C. If exposures to 12 or 15 C were initiated prior to a “transition point,” long delays of cell division were generated. After this transition point, cell division could no longer be substantially delayed by exposure to low temperature. The time of the transition point was somewhat earlier with 15 C than with 12 C treatments. At temperatures higher than 15 C long delays of cell division were not generated regardless of time of treatment.The effects of low temperature on oral morphogenesis were strongly dependent on the stage which was affected. (i) The further development of cells initially in the “anarchic field” stage (stage 1) was immediately blocked at both 12 and 15 C. (ii) Cells initially in the stages of incipient membranelle differentiation (stages 2 and 3) continued to develop at both 12 and 15 C, and formed oral primordia in which all 3 membranelles were clearly differentiated (stage 4). The subsequent progress of these stage 4 primordia depended on the temperature: at 12 C virtually all were resorbed (and cell division was blocked); at 15 C only about 1/3 were resorbed, while the remaining 2/3 completed their development (with the concomitant completion of cell division). (iii) Cells initially in intermediate stages of membranelle differentiation (early stage 4) developed to some extent at 12 C, and then underwent resorpton of oral primordia and blockage of cell division; at 15 C such cells completed their development and division normally. (iv) Cells in which the membranelles and undulating membrane were complete or nearly so (stage 5 and very late stage 4) at the time of the beginning of the cold treatment subsequently finished their development and went thru cell division, even at temperatures as low as 5 C.These results indicate that in addition to a “stabilization point” which occurs shortly before the completion of membranelle development, there is an earlier change in the primordium at the time of the onset of membranelle development, which renders development much less sensitive to direct interference by low temperature.

Notes: SYNOPSIS. Excysted sporozoites of Eimeria meleagrimitis, E. necatrix, E. acervulina, and E. gallopavonis were inoculated into monolayer cell cultures of bovine, ovine, porcine, and human kidney. E. meleagrimitis developed only in bovine embryonic kidney. Mature schizonts were found in the 11th, 16th, and 20th serial passages, but only immature schizonts were in the 4th and 6th passages. E. necatrix developed to mature schizonts in the 3rd, 4th, 6th, 11th, 16th, and 20th passages of bovine kidney and also to immature schizonts in the 175th and 189th passages of PK-15 (cell line porcine kidney). Schizonts, however, did not develop in the 140th and 145th passages of CCI-33 (cloned PK-15). Neither E. meleagrimitis nor E. necatrix developed in the primary, 1st or 2nd passages of bovine embryonic kidney, primary porcine kidney, 45th and 52nd passages of a human embryonic kidney cell line, or in the primary, 5th and 18th passages of ovine kidney. Eimeria acervulina and E. gallopavonis did not develop in any of the cultures. E. meleagrimitis and E. necatrix probably completed only one asexual generation in culture. The structure of mature schizonts of both species differed greatly from those in the natural host. Schizonts of E. meleagrimitis present at 48 hours were small (13–18 by 12–14 μ) and contained only 12–28 merozoites that were 3.2–3.8 μ long. At 48 hours, E. necatrix schizonts were 15–18 μ in diameter or less and contained only 15–20 merozoites (2.0–3.5 μ long); at 96 hours they were 50–70 by 10–35μ and contained either hundreds of small merozoites (2.0–3.5 μ long) or a lesser number of larger merozoites (9–11 μ).

Notes: SYNOPSIS. In heavily endemic collecting sites in Panamá and Colón Provinces, Republic of Panama, 14.7% of Ameiva ameiva and 8.5% of Basiliscus basiliscus were injected with Besnoitia darlingi. Single infected specimens of A. leptophrys and A. festiva were also taken, these being new host species records for this parasite. Infections were found only in the older lizards.Initially, virulence of the lizard parasites for white mice was low but increased with successive mouse passages. Concomitantly, the cyst-forming capacity of the strain diminished with successive mouse passages. No relation between initial virulence of the lizard parasites for mice and subsequent virulence after 16 or 17 mouse passages was recorded.The original description of B. panamensis (a synonym of B. darlingi) is emended on the basis of extensive material to include cyst diameters of 200–500 μ; also, the liver, mesentery, and tunica propria of the testis occasionally contain cysts. Cysts are frequently macroscopic and on the surface of organs so that they can be seen on casual inspection. B. sauriana Garnham, 1966 is a synonym of B. darlingi.

Notes: SYNOPSIS. An electron microscope study of microgametocytes and macrogametes of Eimeria nieschulzi Dieben, 1924 revealed that they lie within vacuoles bounded by a host unit membrane. The vacuole surrounding the microgametocyte contains granular material. The vacuole around the macrogamete is narrower and contains vesicles and membranes. Micropores were seen on the surface of the plasma membrane of microgametocytes and macrogametes. Microtubules were seen in macrogametes. Young microgametocytes and macrogametes have a similar cytoplasmic matrix, mitochondria and nuclei. Glycogen granules apparently develop around vacuoles in both microgametocytes and macrogametes. Glycogen granules were also seen along the margins of parallel bundles of fibers in microgametocytes. As nuclei of the microgametocyte divide, they move to the periphery of the parasite. Three basal bodies, each with 9 fibers in triplet form, develop in association with each nucleus. Microgametes have 2 free flagella and a central short, attached flagellum. Basal granules lie along the outer fibers of the central flagellum. Each microgamete has an elongate mitochondrion in close contact with the nucleus. In macrogametes wall-forming bodies develop in lacunae in the cytoplasm. Smaller dark bodies with areas of low density were also seen. Wall-forming bodies and dark bodies move to the periphery of mature macrogametes.

Notes: SYNOPSIS. In the nearly mature macrogametes of Eimeria auburnensis, the cell membrane is a unit membrane, with underlying and overlying osmiophilic layers usually present. Cup-shaped micropores were occasionally seen. Smaller, V-shaped invaginations were also found in considerable numbers at the surface. At the deepest point, these invaginations were bounded only by a unit membrane. Immediately adjacent to this point, vesicles with homogenous electron-pale contents bounded by a similar unit membrane, were frequently seen. Pinocytosis evidently occurs at the site of these invaginations. Numerous folds of the host cell membrane bordering the vacuole in which the parasite lay extended about 0.1–0.7 μ into the vacuole. These “intravacuolar folds” varied in depth and number in different specimens. In some, the majority of folds had apparently become disconnected from the host cell membrane. A highly developed smooth endoplasmic reticulum occurred in the adjacent host cell cytoplasm. The intravacuolar folds may assist in transfer of nutrients, including membrane material, from the host cell to the parasite. The evidence indicates that in this species of Eimeria nutrients are taken into the parasite primarily as fluids by pinocytosis and possibly other processes.

Notes: SYNOPSIS. Sexual reproduction of up to 50% of the cells from 9 cultures of Stentor coeruleus was observed repeatedly for several months. Photomicrographs were taken of mating pairs, and a number of new observations were made, including the ability of well fed cells (containing food vacuoles) to conjugate, the ability of a high percentage of cells (approaching 50%) in a culture to mate at one time, a more detailed description of the region of cell attachment as viewed from the frontal fields of the partner cells, and the ability of one partner to twist off and leave its oral area attached to the other member of the pair.

Notes: SYNOPSIS. Comparison of RNA molecules between certain protozoa using the technic of nucleic acid hybridisation revealed that there are complementary sequences for ribosomal RNA molecules in the genomes of such cells. Furthermore the genes for ribosomal RNA have been conserved during evolution in this group of organisms. On the other hand, RNA molecules from these protozoa which can be considered to be “messengers” show little in the way of sequence relationships. By utilising the technic of hybridisation it was found that Oxytricha can compete effectively against Paramecium ribosomal RNA for Tetrahymena DNA but the ribosomal RNA sequences of the latter could not compete completely against Paramecium ribosomal RNA for Oxytricha DNA. The result is interpreted to show that different ribosomal sequences were hybridising with each of the DNA samples from Tetrahymena and Oxytricha. A general interpretation of this result in terms of ribosome evolution is presented.

Notes: SYNOPSIS. Strains of Tetrahymena pyriformis, including amicronucleate strain GL and representatives of 9 syngens, have been examined to determine the patterns whereby cortical features vary with numbers of ciliary meridians. The characteristics scored were the positions of the contractile vacuole pores (CVP's), the extent of the area within which CVP's develop, the incidence of supernumerary CVP's, and the number of postoral meridians. Intrasyngenic comparisons were possible in 6 syngens and permitted an assessment of intrasyngenic variation for these characteristics. Only the CVP positions appear to be reasonably constant within syngens in the strains examined. On the basis of this criterion the syngens can be arrayed in an approximate order of 1, 3, 7, 6, 8, 9, 2, 5, GL and 4; the angle formed between the central axis, the stomatogenic meridian and the CVP's is most acute in syngen 1.

Notes: SYNOPSIS. The bionomics of Labyrinthula Cienkowski and the validity of the family Labyrinthulidae Haeckel are reviewed. The structure, physiology (including nutrition), locomotion, ecology, and possible pathogenicity for eel-grass (Zostera marina L.) are discussed. The uniqueness of its gliding motility along slime tracks, lack of phagotrophy, and poorly understood congregation tendencies emphasize the present taxonomic isolation of the group. Further interest attaches to some species because of their steroid requirements.

Notes: SYNOPSIS. Sporozoites of L. simondi were maintained in a viable state for 7 months in liquid nitrogen. Comparison of parasite development initiated with fresh and frozen sporozoites showed a delay in development of each stage studied. Comparisons of prepatency, first elongate gametocytes, peak density of round and elongate forms, anemia and disappearance of megaloschizonts were made. In each phase there was a delay of 2–3 days in ducks infected with frozen sporozoites.

Notes: SYNOPSIS. Ten strains of Acanthamoeba from freshwater habitats were isolated in clonal cultures. Studies were made of trophic structure, nuclear division, cyst structure, some aspects of cytochemistry, and other characteristics. One strain was identified as A. castellanii (Douglas, 1930), one as A. astronyxis (Ray and Hayes, 1954), and 8 as A. polyphaga (Puschkarew, 1913). Strains of Acanthamoeba isolated by other workers were also examined comparatively.The pattern of nuclear division in all strains resembled that in metazoan cells, with the exception that centrioles were never found. Trophic amoebae had a PAS-positive surface outline. Cyst walls were strongly PAS-positive and also gave a positive test for cellulose with zinc chloroiodide.The genus Acanthamoeba Volkonsky, 1931 is re-defined, being distinguished from Hartmannella Alexeieff, 1912, emend. Volkonsky, chiefly by the formation of tapering, hyaline pseudopods (acanthopodia) and by a cyst made up of an ectocyst and a polyhedral or stellate endocyst, with excystment by removal of opercula. Other characteristics found in all strains include a distinctive food cup, the presence of many small refractile globules in the cytoplasm of trophic amoebae, and a cyst wall containing cellulose. The degree of spindle convergence, employed by Volkonsky as a generic criterion, was unusable.Differential diagnoses based principally on cyst structure are offered for A. castellanii, A. astronyxis, and A. polyphaga. The strain previously called Mayorella palestinensis Reich, 1933 is a distinct species of Acanthamoeba.