ALBERT

Notes: Book reviews in this article:THE CHESA PHOTOGRAMMETRIC EXPERIMENT (Technical Publication

Notes: The salient features of a method of analytical triangulation operating directly on single photographs are described, and the close analogy with geodetic triangulation computation is demonstrated.Any combination of photographs, whether in stereo pairs, stereo triples, strips, sub-blocks or blocks, is handled by forming the set of observation equations for each individual photograph in turn, and then taking all these sets together and solving them simultaneously by the method of least squares.Special procedures for dealing with very large numbers of variables are discussed, and certain applications of the method are indicated.

Notes: The rate of ingestion of cytoplasm from its prey ciliate by Podophrya collini shows a maximum at 18°C. The rate of ingestion is the same for all active tentacles during the feeding period. Calculation of the amount of cytoplasm ingested from rate measurement and from dimensional alterations of ciliate and suctorian during feeding indicates conformity to the hypothesis that the motive force for ingestion results from integrated activity of the total cell and not from autonomous activity of the tentacles alone. The estimated motive force approximates 0.2 atmosphere. Data is presented to indicate that energy to maintain this motive force is derived from the normal oxidative metabolism of the suctorian.

Notes: Hepatozoon procyonis, n. sp., is described from the raccoon Procyon lotor from southwestern Georgia. Mature gametocytes in monocytes in blood smears and schizocysts and developing gametocytes in sections of heart tissue were observed and described. A Hepatozoon was also found in the fox squirrel Sciurus niger.

Notes: In Paramecium there is no known correlation between the direction of electric current through the membrane and of ciliary beat. One reason is that the Ludloff phenomenon, an anodal shift in the limit of the area of reversal with increased current strength, has seemed contradictory to most other data. However, by assuming Paramecium to be a core conductor immersed in a volume conductor and by applying the laws of polarizing currents it is possible to explain all existing data on reversal of normal ciliary action, and also on activation of cilia in immobilized specimens by electrical current. It is assumed that a threshold degree of depolarization of the normal membrane potential or of current density causes reversal. The Ludloff phenomenon is caused by anodal progression of this degree of depolarization with increasing membranecurrent. If it is also assumed that an increase in the membrane potential of immobilized specimens causes activation in the normal direction, one can predict anodal activation, progression of reversal with decrement in velocity, time course of development of excitation, ancdal stimulation upon “break.” stimulation by linearly rising currents, relative refractory and supernormal periods, effect of angle of orientation, and effect of acetylcholine and antiacetylchoiine esterase. Assumption of a neuromotor system is not needed. However, if available data are interpreted in the manner commonly used for nerve it can be concluded that an active accommodative process exists and possibly also a local excitatory state. A recent “dipolar” theory of galvanotaxis is not acceptable because it does not include ciliary reversal.

Notes: The morphologic phenomena of the conjugation of Paramecium caudatum are analysed by transverse sectioning of couples at the level of the junction zone. This orientation allows exact determination of the adjacent surfaces (which strongly suggests the absence of a paroral cone) and their relation to the ciliary fields. The modifications of the outer pellicle are studied with the electron microscope. It is shown that cytoplasmic communications occur at the top of the ridges which limit the periciliary depressions. The kinetosomes remain apparently intact but cilia and trichocysts disappear. An active role by the latter organelles is suggested for the union of the two conjugants.

Notes: Resistance to sulfanilamide has persisted in a strain of Chilomonas Paramecium for 255 transfers (63 months) in a drug-free medium. In attempts to modify resistance, stocks derived from sulfonamide-resistant and normal strains have been acclimatized to and then maintained in media containing p-aminobenzoic acid at 5.0, 10.0, 15.0 and 20.0 mgJ100 ml. Each PABA-acclimatized strain was more susceptible to sulfanilamide than its parent stock. In other words, sulfanil-amide-resistant strains lost their resistance and normal strains became hypersensitive. One strain, adapted first to sulfanilamide, subsequently to PABA (15 mgJ100 ml) and again to sulfanilamide, showed a loss of and finally a restoration of sui-fonamide-resistance (but to a degree somewhat lower than the original level).

Notes: DL-serine, DL-methionine or DL-serine + DL-methionine in excess inhibited the growth of Tetrahymena pyriformis H. Excess serine was most inhibitory at high concentration of folic acid, whereas the effect of excess methionine or methionine + serine was most pronounced at low levels of folic acid. Inhibition due to excess serine was relieved by raising the level of methionine or by adding pyrimethamine to lower the effective folic acid level, and was intensified by adding Dl.-ethionine or by raising the level of folic acid. Similarly, inhibition due to excess methionine was relieved by supplying more serine or adding DL-ethionine (which reduced the amount of available methionine) and was intensified by adding pyrimethamine. Inhibition by excess methionine + serine was reversed by increasing threonine, provided there was ample guanine present. Low levels of guanine or the presence of 8-azaguanine prevented this reversal. Comparisons are made with the work of others.

Notes: Autogamy in Frontonia leucas is described for the first time. The process appears to occur at irregular intervals. From 7 to 10% of the individuals are affected. The beginning of autogamy is marked by a swelling of all the micronuclei which take part in the first two maturation divisions. The third division however affects only one of the second division products. Occasionally two or three may divide. A paroral cone is not prominent. But a small area close to the peristome is distinguishable as the region where the pronuclei fuse. The syn-karyon divides four times. Some of the division products disintegrate, after which 8 to 9 bodies are left which become differentiated into 4 to 5 macronuclear anlagen and 4 micro-nuclei. Mitotic division of the micronuclei results in their increase in number in the daughter individuals after metagamic divisions. Changes in the macronucleus during autogamy consist in its fragmentation and later absorption in the cytoplasm. There is some indirect evidence of a relationship between the dissolution of the old macronucleus and the development of the new.

Notes: An electron microscope study of Plasmodium lophurae maintained in vivo and in vitro provided information concerning the sequence of events during reproduction, and the role of the cytoplasm in this process.Contrary to the generally held opinion that nuclear fissions precede cytoplasmic division, it was found that the last nuclear fission takes place during advanced stages of cytoplasmic segmentation. This study also supplied evidence that in addition to repeated nuclear divisions, a number of changes occur in all major components of the cytoplasm. These changes are considered as preparatory for reproduction. The cytoplasm continues to be active during the formation of merozoites. At this stage a segregation of cytoplasmic components takes place resulting in the incorporation into the offspring of a condensed cytoplasm containing all the organelles. The watery part of the cytoplasm with the lipids and food vacuoles is withheld and at the end of reproduction forms the residual body, a separate structure bound by a membrane.

Notes: Ophryoglena hypertrophica is distinguished by its tomites and its pyriform theronts; by its elliptical and flattened macronucleus with 2 or 3 coupled micronuclei; by its large trophont; by its tomont covered with a thin mucous layer at the interior of which are formed 4 or 8 tomites closely bound one to another. Its physiological evolution is characteristic; the tomite when it comes out of the tomont undergoes a secondary encystment and then becomes the theront. Sometimes the tomite is rostrated and is not attracted by the tissues; the tomite undergoes as before a secondary encystment, but divides inside the cyst. This type also produces complete or partial particular palintomies and regularly forms resistant cysts.

Notes: Intraspecific chemotaxis between gametes was demonstrated in Chlamydomonas moewusii Gerloff var. rotunda nov. var. which was previously used as C. sp. 24 (Tsubo Y. 1957). a heterothallic isogamous species from Japan. The reaction is unidirectional; the “+” gametes are attracted by the “—” gametes or cell-free supernatant of medium in which the :“-” gametes were suspended. In a study with 4 other isogamous heterothallic Chlamydomonas — C. moewusii Gerloff, C. eugametos Moewus, C. reinhardi Dangeard, and C. morewusii Gerloff var. tenuichloris nov. var. — none of them revealed any intraspecific chemotactic behavior. However, as with the “—” gametes of C. moewusii var. rotunda, both mating types of C. moewusii, C. eugametos, and C. moewusii var. tenuichloris were interspecifically attracted by the supernatant of the “—” culture of C. moewusii var. rotunda. Only C. rein- hardi showed no chemotactic behavior in intra- or interspecific combinations.Although chemotaxis occurred in the above-mentioaed combinations, neither agglutination nor pairing ner zygete formation followed at all in the same combinations. The“;–” cells of C. moewusii var. rotunda killed by osmium vaper and then washed no longer produced the chemotactic agent, but did agglutinate with living “+” cells. Therefore, evidently, chemo-taxis is a separate step from agglutination and zygote-for-mation yet does not seem necessary in the mating of isoga-mous Chlamydomonas. Nonetheless, since this activity appears not in the vegetative but in the gametic stage, it seems to concern the sexual activity of the cells. In preliminary studies the chemotactic agent produced by C. moewusii var. rotunda was shown to be volatile.

Notes: A microsporidian infection in a laboratory clone of Hydra littoralis has been observed, and the parasite has been tentatively identified as a species of Plistophora. Infected hydra continue to bud and regenerate normally and show no significant physiological or morphological changes. Sexual crossing of infected and non-infected animals shows that the infection is transmitted by the ovum but not by the sperm. Continuous exposure of infected hydra to Fumidil B in solution resulted in the disappearance of all Plistophora spores after a five week period of treatment, and the clones of the treated animals have remained parasite-free for more than a year.

Notes: Patterns for free and protein amino acids and related substances were determined for Tetrahymena limacis and 7 strains of T. pyriformis from axenic stationary phase cultures grown at 25° C by means of 2-dimensional chromatography in a butanol-acetic acid and phenol solvent system with ninhydrin and other polychromatic indicators. A uniform protein amino acid (PAA) pattern was observed in all strains. There were 14 color spots indicating 19 amino acids (including cysteic acid), identified as follows: alanine, arginine, aspartic acid, cysteine/cystine, cysteic acid, glutamic acid, glycine, leucine/isoleucine/phenylalanine, lysine/histidine, proline, serine, threonine, tyrosine, valine/methionine.The following free amino acids and related substances (FAAs) were identified with 14 spots (several different from these for PAA patterns) found in all strains: alanine, arginine, asparagine, aspartic acid, glutamic acid, glutamine, glycine, leucine/isoleucine/phenylalanine, lysine histidine. proline, serine, threonine, tyrosine, valine/methionine. T. limacis and strains LI and Gf-J of T. pyriformis exhibited these only. Chromatograms of 5 strains of T. pyriformis (PR. F. L3 WH52, HS), however, also contained 1 to 4 spots representing certain of the following substances: Cysteic acid, cysteine/cystine, taurine, and the unknowns X1, X2, and X3, having Rf's of 0.33, 0.79, and 0.72 respectively in 4:1 phenol-H2O system Excepting for F and L3, which were similar, the T. pyriformis strains showed quite different distributional patterns of these substances at 25°C. Other deviations in the distribution of the 6 compounds were noted in the chromatograms of 10° and 35° cultures of WH52 and HS. These findings on FAAs and PAAs are tabulated, along with those of previous investigators, to furnish comparisons on 13 strains of Tetrahymena pyriformis, T. limacis and 9 other species of protozoa.

Notes: Three new species of Trypanosomatidae were isolated from three species of bugs: Leptomonas leptoglossi from Leptoglossus phyllopus, Crithidia acanthocephali from Acanthocephala femorata, and Blastocrithidia euschisti from Euschistus servus. All were cultured axenically and on avian embryo membranes. In addition to differences in morphology the three organisms displayed different growth rates in the chorio-allantoic fluids of duck and chick embryos incubated at 30°C. L. leptoglossi grew most abundantly. B. euschisti barely maintained itself while C. acanthocephali occupied an intermediate position.When the temperature of incubation was raised to 37°C, there was continued multiplication of L. leptoglossi and C. acanthocephali, but there was no growth of B. euschisti in either duck or chick embryos.It is suggested that the criteria of morphology, cultural characteristics in vitro and in vivo, plus physiological characters be used as future aids in classification of the Trypanosomatidae.

Notes: SYNOPSIS: Crithidia fasciculata was cultured in a modification of the nutrient medium described by Cowperthwaite in 1951. Carbon dioxide, lactic acid, succinic acid and ethyl alcohol were produced by the organisms during anaerobic conditions. Hexokinase, enolase, alcohol dehydrogenase and glucoses-phosphate dehydrogenase were demonstrated in ho-mogenates of the flagellates. Aldolase, phosphohexokinase and lactic acid dehydrogenase could not be demonstrated.

Notes: Application of fragmentation and thin-sectioning techniques to Tetrakymena pyriformis, Colpidium compiles and Glaucoma chattoni has permitted an analysis of the ultra-structure of their silverline and fibrillar systems. The classical silverline system consists of a mosaic of flat, membrane-bound blisters whose rims represent the sites of selective silver deposition. Cilia and protrichocysts emerge between adjacent blisters. I The pellicle consists of the membranes outlining the blisters, overlain by a continuous outer membrane that covers the whole cell and cilia. Fibrillar structures, which are not argentophilic, include: (1) tapering, striated kinetodesmal fibers arising singly from the kinetosomes, passing to the right and anteriad, and overlapping to form a loose bundle accompanying each kinety; (2) a longitudinal fibril band immediately beneath the pellicle at the right of each kinety, consisting of overlapping individual fibrils; (3) a transverse band of fibrils arising at the left side of each kinetosome and passing to the left under the pellicle; and (4) a set of postciliary fibrils arising at the right posterior edge of each kinetosome and passing posteriad under the pellicle. The fibrils of sets (2), (3), and (4) all are about 20 Mμ in diameter and appear tubular in cross-section; they are very unlike the heavier, solid kinetodesmal fibers. None of the fibril sets directly interconnect, although transverse and postciliary fibrils end in the vicinity of the longitudinal fibril band.

Notes: The structure of a cilium in Nyctotherus ovalis is that usually found: two single central filaments surrounded peripherally by nine double filaments; the whole is encased in a ciliary membrane continuous with the pellicle. The two central filaments end in a single enlarged bulb just above a septum, located at about the level of the pellicle, whereas the nine double filaments extend inward to form the cylindrical basal body, which is open at its inner end. Inside the basal body are granules àrranged in rows parallel to its sides. These granules may have significance in the origin of new basal bodies as well as in the outgrowth of new cilia. The latter may have been observed in a few instances. Parallel to the pellicle are two series of fibrils, one median and one inner, connecting adjacent basal bodies. Fibrils extend from the inner end of each basal body, these converge and extend deep into the ectoplasm, often becoming lost in a pattern of equilateral triangles, arranged to form hexagons. These features are clearly seen in the peristomial membranelles, where the basal bodies of the four rows of cilia are close together, separated from adjacent membranelles by a protoplasmic shelf and supported by a mass of fibrillar material comprising the peristomial ectoplasmic band. This broad band extends to the inner end of the peristome whence it returns along the opposite wall as a narrow mass of fibrillar ectoplasm without basal bodies. Peripherally the fibrils are condensed into fan-like bundles; internally they often form a network of equilateral triangles arranged to form hexagons, with corpuscles at the intersections. Trichite-like structures are also found in the peristomial groove and tube; these are connected to both the basal bodies and the fibrillar network.The functions, origin and development of this complex infraciliature during fission constitute one of the yet unsolved morphological problems in such complex ciliates.

Notes: The foed vacuoles of Paramecium aurelia, when examined in the electron microscope, are seen to be surrounded by small secondary vacuoles 0.05 - 0.2 μ. in diameter. Similar small vacuoles also surround the deepest part of the buccal cavity. Young focd vacuoles, i.e. those containing well preserved bacteria, are encircled by a smooth. vacuolar membrane. In older food vacuoles the vacuolar membrane in a transverse section often appears more wavy with small gulfs and protuberances. It is suggested that the small surrounding vacuoles are formed by the vacuolar membrane of older vacuoles by means of a process similar to pinocytosis. There is no evidence, however, that formation of small surrounding vacuoles takes place by pinocytosis in young food vacuoles. Examination of the cytoplasmic membrane of the deepest parts of the buccal cavity shows a similar prccess of vacuole formation by pinocytosis.

Notes: Tritrichomonas foetus, Pentatrichomonas gallinarum, and nasal and fecal forms of Trichomonas suis grew well in NIH Thioglycollate Broth with 1% beef serum, and produced acid end-products. Succinic acid was the major acid produced by T. foetus P. gallinarum, and the nasal T. suis, accounting for over 50% of the total acid for each. The fecal T. suis produced more lactic than succinic acid; about 45% of the total acid was not accounted for. Pyruvic acid was found in small amounts in all cultures. The lactic/pyruvic ratio was about 2.5 for the two swine forms, and about 1.0 for the other two. The nasal form of T. suis produced much more total acid than the others.O2 uptake, CO2 production, H2 evolution, and anaerobic acid formation varied with age of organism. Respiratory activity was highest at 12 hours but varied considerably thereafter. The nature of the buffer used in manometric experiments also affected the results.Glucose, mannose, fructose and galactose most stimulated respiration. Disaccharides were slowly utilized (lactose and sucrose were not used by P. gallinarum). In a few cases lactate, pyruvate, formate, and malate stimulated O2 uptake.Evidence was obtained for hexokinase, phosphohexoisomer-ase, phosphofructokinase, aldolase, and glucose-6-phcsphate dehydrogenase in all 4 organisms. Phosphoglucomutase was demonstrated in T. foetus and the fecal T. suis. T. foetus and P. gallinarum showed evidence of phosphoglyceromutase and enolase. T. suis (fecal) and P. gallinarum had malic dehydrogenase, and P. gallinarum gave evidence of “malic enzyme” activity. Formic dehydrogenase activity was marked in all and presumptive evidence for a formic hydrogenlyase system was obtained for T. foetus and P. gallinarum.Study of reactions involving pyruvate and malate (with a possible linkage to a hexose monophosphate shunt) might perhaps provide a key to a better understanding of trichmonad metabolism.

Notes: Glaucoma chaitoni. A has been grown in a medium free from protein. Twelve amino acids, seven B-vita-mins, a purine and pyrimidine were essential. Long-chain unsaturated fatty acids and their triglycerides, synthetic phosphatides, and carbohydrates were stimulatory. Oleic acid- containing lipids were best. The significance of the phosphatide activity and the applicability of the results of this work to problems in tissue cell and bacterial cultivation are discussed.

Notes: Some conditions for optimum accumulation of vitamin B12 by resting Euglena gracilis cells were studied. Accumulation involves intracellular binding, as confirmed by disruption of the cells and differential centrifugation. At least 70% of the intracellular B12 was attached to sedimentable particles, apparently to the mitochondrial and cell wall-membrane fractions. The latter contains a heat-labile substance which rapidly binds B12.

Notes: Tritrichomonas foetus survives when frozen in the presence of 1 M glycerol after growth in cysteine-peptone-liver-maltose (CPLM) medium. In the present study, survival upon storage was better in a chest-type freezer at a constant −21°C than in an upright freezer from which were recorded cyclic temperature fluctuations between −23 and −25° or in a dry-ice chest with a nominal temperature of −72°. By the use of special thermocouples inside the freezing tubes, it was found that the temperature fluctuated between −22 and −24° in the chest-type freezer, between −19 and −30° in the upright freezer, but rising as high as -2° when the door was opened and samples were removed, and markedly in the dry-ice chest as the dry ice melted and was replaced, sometimes rising to as high as −27°. The poorer survival in the latter 2 freezers was considered due to temperature fluctuation.When equilibration with glycerol was carried out at room temperature, survival upon subsequent freezing was better following rapid equilibration (glycerol added all at once; equilibration time, 1 hour) than following slow equilibration (1/6 of the final amount of glycerol added each hour for 6 hr.; equilibration time, 7 hr.).Survival was extremely poor following either rapid or slow equilibration in the refrigerator (4°). Since T. foetus can grow indefinitely at 37° in the presence of 10% glycerol and since it is protected by glycerol when frozen, there is a critical zone near 4° in which glycerol appears to be toxic.Buffering the storage medium to pH's 6.3 to 7.1 with glycyl-glycine increased survival upon freezing, but buffering to the same pH's with triethanolamine had no significant effect upon survival, and buffering to pH's 7.1 to 7.5 with phosphates decreased survival upon freezing.

Notes: In three Patagonian cavies (Dolichotis Patagonia) which died in Dutch zoological gardens, coccidia were found. They were determined as Eimeria dolichotis (Morini Boero & Rodriguez, 1955). Cross-infection experiments with guinea-pigs exclude the identity with Eimenc cmvimt.

Notes: The effect of a series of phenylalanine- or tyro-sine-containing peptides and derivatives on the oxygen consumption of washed Tetrahymena performers W cells was determined. Peptides gave greater stimulation of oxygen uptake than phenylalanine or tyrosine alone. Intermediary reaction products of phenylalanine metabolism were not oxidized, nor were derivatives of phenylalanine in which the amino group was blocked. The action of several tyrosine or phenylalanine ant metabolites was determined. It was demonstrated that extra-cellular hydrolysis of glycyl-L-phenylalanine and alanyl-L-phenylalanine took place when these peptides were incubated with washed protozoa.

Notes: SVXOPSIS. Parasites belonging to the genus Cytamoeba have been found in amphibians from central and northern California. The infected animals and their numbers were (URODELA) Aneides flavipunctatus (2), A. lugubris (29), Batrachoseps a. atttnuatus (81). Dicamptodon ensatus (2), and (SALIENTIA) Rana b. boyli (1). The rates of infection varied between 0.6% and 29.3%, and the number of parasites per infected cell ranged from one to seven.Preparations stained with haematoxylin and Romanowsky dyes indicated several types of parasite: some were homogeneous, others possessed several dark staining granules and some possessed large, dark staining central bodies or peripheral dark staining rims. Parasites were seen in the erythrocytes, the plasma and, occasionally, in endothelial cells and monocytes. They were found in the peripheral and heart blood and in the blood of the liver, spleen, kidneys and lungs. Cell division was common in erythrocytes, and yielded daughter cells of identical size. In some cases, chains of 3 to 5 individuals were seen and, rarely, three bodies, in a cloverleaf configuration, were produced as the result of a single division. Following acid hydrolysis, methylene blue-stained parasites showed a peripheral ring of granules, and, in some, a few stained centrally located bodies.

Notes: The literature on the coccidia of the carnivorous mammals of the family Mustelidae has been reviewed. Three species of Isospora are described for the first time from the zoriile, Ictcnyx (Zorilla) capensis (Fam. Mustelidae). Two of these, I. hoogstraali sp. now, and 7. africana sp. nov are considered to be new species, while the third one, I. bigemina var. zorillae var. nov. is recognized as a new variety.

Notes: Electron micrographs of sections through the blepharoplast complex reveal it to be composed of four kineto-somes. In many of the sections the kinetosomes contain dense particles approximately 180-200 A in diameter. The costa is a striated fiber which extends posteriorly almost the entire length of the body. Its slender proximal portion appears to be attached to the base of the kinetosome of the recurrent flagellum. The parabolas fiber is similarly constructed, but is more slender than the costa. It is attached to the base of the kinetosome of an interiorly directed flagellum and subsequently proceeds posteriorly to the level of the nucleus. The costa and parabasal fiber probably serve as anchoring or supportive structures. The size of the costa may reflect its role as a supporting structure for the most highly differentiated locomotors organelle, the undulating membrane.

Notes: A survey of antigenic types, as revealed by immobilization reactions, among 78 strains of variety 1 of T. pyriformis grown in monoxenic cultures at 25°C discloses a minimum of six distinct classes. These are called the H serotypes, and are designated as types Ha, Hb, Hc, Hd, He and Hf. The terminal members of highly inbred series (Families A, A1, B, D, etc.) are of a single immunological class, but different inbred series show different serotypes. Early representatives of the inbred series show in contrast considerable serotypic variation. The distribution of serotypes is generally consistent with the genetic hypothesis developed in a parallel study, but new serotypes arise occasionally through some mechanism not yet adequately studied.

Notes: Two types of polymorphism, differing greatly in stability characteristics, have been recognized in Tetrahymena vorax strain V2. The basic life history involves three stages: a microstome, a macrostome, and a cyst. The appearance of each of these stages is dependent upon conditions of substrate availability, i.e., macrostomes persist in the presence of suitable ciliate prey, microstomes persist in the presence of bacteria or organic nutrient solutions, and cysts appear under conditions of starvation.Superimposed upon the basic life history is a second level of polymorphism: three markedly different types of sublines have been obtained from a single parental clone. No intermediate types have been observed. When grown under identical controlled conditions, the three types of sublines differ significantly in cell and nuclear size, meridian number, growth properties, competence to form cysts and macrostomes, and serotype. Each subline of a given type is subject to transformation into one or both of the other types. These transformations are usually spontaneous events with very low frequencies, although certain transformations may be induced. Once a transformation has occurred, the new phenotype is inherited by subsequent generations of cells for an indefinite period in a way which is independent of environmental influences. The available information suggests that the three types of sublines are not the result of gene mutations, but rather represent alternate epigenetic stable states of a single cellular system.

Notes: The flagellate Chlorogonium elongatum has been studied in the electron microscope by thin-sectioning techniques. The nucleus, limited by a porous membrane, contains a large nucleolus and some dense masses, probably of chromatin. When the medium is rich or the culture young, the chloroplast has few lamellae, and very few pyrenoids. Inversely, when the medium is poor or jthe culture old, the lamellae are abundant, appearing as piled discs or as a tortuous lamellar system. The pyrenoids are then numerous and are surrounded by starch grains. They are composed of an opaque, finely granular substance, and are never traversed by chloroplast lamellae. The stigma, within the chloroplast, is a circular or oval plate composed of a single tier of dense granulations. The cytoplasm contains mitochondria which are concentrated near the pellicle of the cell, an endoplasmic reticulum, an abundance of ribo-nucleoprotein particles or ribosomes, and a Golgi apparatus. These organelles resemble those observed in other protozoa. The two fiagella are encased in cylinders situated at the anterior end of the cell. At the base of the fiagella are the basal corpuscles or kinetosomes, which repose within a cupule. A dense granule which probably corresponds to the centrosome appears near this structure.

Notes: Colpoda cucullus forms two kinds of resting cysts: stable cysts which withstand freezing and need 24 hours for activation, and unstable cysts which do not survive freezing, but are activated within 3-4 hours. ImM 2,4-dinitrophenol has no effect on stable cysts, and increases the respiration rate of unstable cysts by 100%. 1 mM methylene blue increases oxygen consumption in both stable and unstable cysts, by 200% and 400% resp. The results suggest that the inhibition of metabolism is more complete in stable cysts. These differences are not correlated with nucleic acid level, as both kinds of cysts contain approximately equal amounts of RNA.

Notes: Total lipids of several protozoa were determined and found higher than in most other microorganisms. The lipid content in a phytoflagellate, Ochromonas malhamensis, could be increased by excess nicotinic acid or deficiency in nitrogen supply. Cell multiplication and lipid synthesis were unaffected by inhibitors of vitamin synthesis such as penicillamine, pan-toyltaurine, or pyridine-3-sulfonic acid, up to 100 mg%. The phytoflagellates, O. danica, O. malhamensis, Euglena gracilis, and the photosynthetic bacterium Chlorobium limkola contained large quantities of non-saponifiable lipids: ergesterol was identified as a major component of this lipid fraction. Sterols were not found in the bacteria, Streptococcus faecalis, Rhodopseudomonas palustris; the algae. Cyanidium calidarnm. Anacystis nidulans, and Porphyridium cruentum; and the protozoan Tetrahymena pyriformis.

Notes: Tetrahymena paravorax RP was cultured axenically in a medium of known chemical composition (within the limits of contemporary standards of chemical purity). In this medium, it required 12 amino acids, 6 B-complex vitamins, a purine, a pyrimidine, and inorganic salts. A sterol or sterol ester was necessary for optimal growth. Plant and animal 3 β-OH sterols with saturated and unsaturated ring systems, and with a variety of side chain structures, were active. Several methylated sterols suggested as intermediates in cholesterol synthesis were inhibitory.

Notes: Hexamastix dobelli n. sp. (Trichomonadidae) is described from the large intestine of the starred tortoise, Testu-do elegans Schoepff. This is the first species of Hexamastix to be reported from a chelonian. The organism is pyriform, oval, or round in shape. There are five anterior flagella, of which two are long and three short and a single recurrent flagellum, which equals the short anterior flagella in length. The axostyle is very slender and projects for some distance outside the body. The nucleus contains three to six granules and has no endosome. The pelta is crescent-shaped and the parabasal body is rod-like. Perinuclear granules are present in the anterior half of the body. The parasite is 6.0 to 16.5 μ long, 2.0 to 10.3 μ wide and the diameter of nucleus is 2.5 μ.

Notes: Seventy-nine adult birds in 8 species were examined at autopsy for the presence of Trypansoma avium. Films of thoracic blood were stained in Giemsa and later searched for trypanosomes. Marrow was removed from femora and humeri, mixed with Ringer's solution, and examined direct for living flagellates. Sixty-four birds (81%) showed positive marrows; 5 (6%) had positive bloods. In the 15 birds with negative marrows, only 2 had trypanosomes in the blood. These data emphasize the advantage of marrow over blood examination in determining the incidence of avian trypanosomiasis and point up the excellence of fresh marrow examination in such studies.

Notes: Eimeria leucopi n. sp. (Sporozoa) is described from oocysts in the feces of the deer mouse Peromyscus leu-copus (Rafinesque) taken in the vicinity of Durham, North Carolina. The oocysts are ellipsoidal, occasionally ovoid, and rarely round, 14-24 ± 14 - 21 μ, mean of 19.2 ± 16.8 μ. Length-width index 1.0 to 1.37, mean of 1.13. Micropyle absent. Oocyst wall composed of 2 layers. Clear residual bodies present. Sporocysts 11.5 - 14.0 ± 6.5 - 8.0 μ, mean 12 0 ± 6.8 μ Stieda body present. Minimum sporulation time about 74-hours, sporulation range about 54 hours. Prepatent period 5 or 6 days with a 6 day patent period. Although the intensity of infection was light in all naturally infected hosts, the incidence of infection ranged from 16.6 to 71.9%E. leucopi could not be transferred to the sympatric golden mouse P. nuttalli.

Notes: Five species of millipedes under investigation revealed the presence of six species of gregarines, five of which are new. A new method for the study of development of the gametocyst is described. A list of the millipedes and their gregarine parasites is given below:

Notes: Four species of Paramecium, P. calkinsi, P. mul-timicronucleatum, P. bursaria, and P. trichium, were treated in the following way. Counted numbers (100 or 200) were irradiated with X-rays in 2 ml air-tight Nylon syringes in steps of 50,000 r begining with this dosage and extending up to at least 450,000 r. For each experiment, the four different species were irradiated simultaneously each in one syringe. Survival and reproduction were then followed for at least 48 hours by expressing irradiated specimens from the syringes into spot plates. P. trichium was the most radiosensitive and recovery and reproduction occurred only after the lower dosages. P. calkinsi was the most radioresistant and showed relatively fast recovery and reproduction even after moderately high dosages. With certain high dosages, reproduction was blocked temporarily for 24-30 hours, after which there was not only recovery from irradiation but a gradually in creased reproductive rate. The greater the dosage, the slower the recovery to reproductive ability.

Notes: Thirty-five species of marine dinoflagellates are described and figured, including one new species, Gymnodinium chukwanii. These were collected by the author during the period February - March 1956. G. chukwanii has affinities to G. splendens and G. nelsoni and their group. The remainder of the paper is concerned with described species.

Notes: A brief summary of the literature exemplifying the indirect lines of evidence leading to the conclusion that -living ciliates conjugate in natural environments is followed by a description of the isolation of potential mates, conjugating pairs and recent exconjugants of Paramecium bur-saria from a pond in Westwood Village. Calif. The data suggest that natural populations of Paramecium pursaria pass through infrequent epidemics of conjugation.

Notes: Amicronucleate (strain W) and micronucleate (strain HAM 3) Tetrahymena pyriformis have been studied by light and electron microscopy. Numerous interphase and individually-sectioned organisms in division stages have been examined. In macronuclei of the amicronucleate organisms (strain W) the time of division is characterized by a rather marked chromatin condensation, by morphological changes in nucleoli, and by the presence of dense granules. In macro-nuclei of the micronucleus-possessing organisms (strain HAM 3) little alteration of the interphase morphology is observed at division. Mitochondrial changes and an increase in the amount and complexity of the endoplasmic reticulum are observed in division in the amicronucleate strain. These results show that macronuclear division is more complex than a simple “pinching-in-two” and that loss of the micronucleus may alter the mitotic events of the macronucleus.

Notes: Nitrogen in cell fractions of Paramecium aurelia varied according to the growth medium. Trichloroacetic acid-soluble fractions of cells were chromatographer. Adenine, adenosine, guanine, guanosine, hypoxanthine, aspartic acid, glutamic acid, histidine, lysine, proline, and phenylalanine were identified. Fyrimidines and xanthine, or their respective ribosides and ribotides, were not detected. Ammonia was released into the medium by both actively growing and “resting” cells. Culture fluids of “resting”cells also contained hypoxanthine and lesser amounts of adenine and guanine. Urea, uric acid, creatine, cretonne, and ailantoin were absent.Pyrimidine nitrogen seems excreted as dihydrouracil. The following enzymes were detected in homogenates and cell-free preparations: nucleotidases, nucleoside hydrolases, and cytidine deaminase. Urease, uricase, adenase, guanase, xanthine oxidase, adenosine deaminase, and 5′-adenylic acid deaminase were not present in this organism.Purine and pyrimidine incorporation into nucleic acids was investigated by the use of radioactive tracers. Guanosine gives rise to nucleic-acid guanine and adenine; adenosine was precursor to nucleic acid adenine only. Formate was incorporated into purines; glycine was not. P. aurelia can interconvert cytidine and uridine; both give rise to nucleic acid thymine. The methyl group of thymine may be derived from formate.

Notes: The slime mold Fuligo septica has been grown bacteria-free in a pure 1.5% agar and oats at a temperature of 25°C. The Plasmodium was also grown under water.

Notes: A variety of ciliates representing most of the major cliate groups were found to adhere to the ends of the tentacles of Podophrya collini. Reduction of ion concentration in the medium, low temperature, and treatment of the food ciliates or the suctorians with agents presumably interfering with choline-acetylcholine balances in the suctorian or ciliate depressed the capture efficiency. Addition of sulfhydryl containing com pounds to the feeding situation and treatments which reduced the swimming vigor of the ciliates gave enhanced capture efficiency. Although killed but unlysed ciliates would not adhere to the tentacle ends, agar particles containing ciliate breis or a mixture of salts plus experimentally determined organic compounds would adhere.

Notes: Schizocaryum dogieli Poljansky & Golikova, 1957, was discovered in four species of the echinoid genus Strongylo centrotus from San Juan Islands, Washington, during the summer of 1960. Specimens subjected to the Chatton-Lwoff silver impregnation technique have revealed that this species has been incorrectly assigned to the holotrich order Apostomatida. The presence of a vestibulum with sparse vestibular ciliature necessitates the transfer of this species to the holotrich order Trichostomatida as defined by Corliss. The infraciliature, certain pellicular organelles and the distinctive nuclear apparatus are described in detail. A discussion of various morphological and behavioral adaptations to its commensal mode of life is included. Detailed evidence is presented justifying the systematic reassignment of S. dogieli to the order Trichostomatida.

Notes: Oocysts of Eimeria acervulina Tyzzer, 1929 were collected at the time of their first massive discharge into the chick intestine, and isolated in the cold by means of continuous centrifugal flotation in high-density media. Maximum numbers (90%) of sporoblastic oocysts were obtained by incubating at 30°C for 10 hr and sporulation was considered complete within 20 hr. The initial Qo2 (dry-weight basis) of 9.5 decreased linearly to 〈 i/3 this value in 20 hr, and more slowly thereafter to very low levels. The QCO2 was higher than Qo2 only during the first 10 hr. A 15% decrease in dry weight in 15 hr was due chiefly to disappearance of alkali-stable carbohydrate, probably identical with glycogen. In the later stages carbohydrate was resynthesized. Lipids were not oxidized during sporoblast formation, but disappeared rapidly betweem 10 and 30 hr. Total nitrogen remained constant, indirect evidence suggesting that protein was not used to supply oxidative energy The change-over from carbohydrate to fat metabolism corresponded with observed changes in the respiratory quotient, and also with near-completion of sporulation. Apparently carbohydrate provided the energy needed for the earlier stages of sporulation, whereas oxidation of lipids supported the teal stages as well as the metabolism during dormancy.

Notes: The taxonomy of the so-called Sporozoa is reviewed, and it is concluded that the group is polyphyletic and should be split into the following independent taxa: (1) The subphylum EUSPORA subph. nov., members of which have simple spores without polar filaments; this subphylum contains the classes TELOSPORASIDA Schaudinn, 1900 and HAPLO-SPORASIDA Caullery and Mesnil, 1899; (2) the subphylum CNIDOSPORA Doflein, 1901, members of which have spores containing 1 or more polar filaments; (3) the class PIRO PLASMASIDA Wenyon, 1926, members of which have no spores, are parasitic in vertebrate erythrocytes and are heter-oxenous; and (4) the class TOXOPLASMASIDA Biocca, 1957 emend., members of which have no spores, have cysts or pseudocysts, and are monoxenous parasites of vertebrates; the latter two groups are not assigned to subphyla but are considered appendages to the Protozoa. A classification to suborders is given of the Euspora.

Notes: Electron and fluorescence microscopy reveal a proplastid about 1 μ in diameter in dark-grown Euglena gracilis quite like those in higher plants. After the cells are placed in the light these structures lengthen, probably in part by coalescence of several proplastids. Full size is reached in some cells after about one day in light. Lamellae, growing as blebs off the inner proplastid membrane, develop in a roughly linear fashion with time, art average of one new lamella appearing after each 6 hours in the light. The maturation of the proplastid thus appears to differ appreciably from that in higher plants since the latter presumably create several lamellae simultaneously, and these appear able to replicate themselves in a geometrically parallel fashion. The question is raised whether the apparent differences in development may not be due to lesser discrimination in observing the sequence in the higher plants, for there are no observations necessarily inconsistent with the sequence found in Euglena.

Notes: A number of isolates of the cellular slime mold, Acrasis rosea, differed from each other in the range of microorganisms on which they could grow and fruit. In a test for the possible occurrence of sexual reproduction and genetic recombination, two of the most widely divergent of these physiological races were studied further. Mixed colonies were obtained in agar plate cultures of Rhodotorula mucilaginosa, a yeast utilized by both. When spores from mature fruiting bodies or amoebae migrating out from the mixed colonies were isolated singly, regrown on Rhodotorula, and tested on a critical spectrum of food microorganisms, about 3-4% proved to be distinct from the original two strains. Although some of these new types remained stable for several transfers, they eventually reverted to one or both of the parental types. The possibilities of explaining the neotypes on the basis of diploidy, heterokaryosis, or mixed cytoplasmic effects are discussed. The occurrence of cell anastomoses and occasional binucleate cells favors the latter two possibilities.

Notes: Specimens of Glaucoma chattoni lacking in oral areas and unable to divide were observed in both axenic and bacterized cultures. The frequency of incidence of astomy rose in the course of continued cultivation of G. chattoni A, which was the strain most extensively studied.Observations on silver impregnated animals from mass cultures, and studies of individually isolated living ciliates, have both led to the conclusion that all cells destined to become astomous pass through a certain definite sequence of events. These axe: 1. Initial damage, not microscopically detectable, predisposes the cell in such a way that within a few generattons all of its progeny become astomous. 2. The ability to complete normal stomatogenesis is lost; the cell cannot maintain normal posterior oral anlagen and also cannot regenerate following damage to the existing oral area. At this stage the cell can still divide, so that astomous opisthes are produced. 3. The existing oral area disappears shortly after the ability to produce new oral areas is lost. Loss of ability to divide occurs simultaneously with loss of oral areas. 4. Finally, there is increasing disorganization of the kineties, gradually decreasing activity and death.The incidence of astomy was compared in several different strains of G. chattoni, including two newly isolated from nature.

Notes: Chilomastix equi n.sp., from the intestine of the Indian horse is described. The normal shape of the body is pyriform, posteriorly drawn out into a spike. The spiral groove is U-shaped and runs from one lateral side to the other. The nucleus is either ovoidal or spheroidal with an eccentric endo-some. Four blepharoplasts are present from which arise the anterior flagella, the cytostomal flagellum and the cytostomal fibrils. The arrangement of the four blepharoplasts differs markedly from the other known species, three being on the anterior border located in one row and the fourth adjacent to the nucleus. The three anterior flagella, arising from the first three anterior blepharoplasts, run backwards. The cytostomal flagellum arises from the fourth blepharoplast and rarely protrudes beyond the broad cytostome. The cytostome has a peculiar shape which distinguishes it from other species. The dimensions of the new species range (in microns) 15.7 to 31.5 in total length, 8.5 to 16.5 in body length proper, 6.0 to 15.5 in breadth and 4.0 to 17.0 in the length of the spike.

Notes: The occurrence of Babesiosoma stableri n. sp. in the erythrocytes of Rana pipiens pipiens extends the host range of babesiosomids to the Salientia. The proposed sequence of developmental stages includes the following events: (1) two successive nuclear divisions of the uninucleate trophozoite produce a tetranucleate organism, (2) cytoplasmic cleavage initiated at each pole of the tetranucleate parasite results in four daughter individuals arranged in a cross-form, (3) the four merozoites originating from the cruciform schizont separate without the formation of a residual mass of cytoplasm, (4) gametocytes which presumably arise from differentiated merozoites do not exhibit dimorphism. The morphology and characteristics of the parasite's development were not altered when B. stableri was experimentally transferred to: R. p. sphenocephala, Rana catesbeiana, Bufo americanus, Bufo woodhousei fowleri, and Bufo terrestris. Experimental infections, with few exceptions, exhibited a peak parasitemia followed by a decline in the number of babesiosomids. Infections persisted at a low level or disappeared during the period of study.

Notes: Dileptus anser is a relatively large multinucleate ciliate (gymnostome) which bears an anteriorly directed non-retractable proboscis. On the ventral surface of the proboscis is found a “feeding groove” which is bounded laterally by large feeding cilia. In the ventral mid-line of this groove is a small fiber which passes from the anterior tip to the cytostome-cytopharyngeal complex, which is located at the base of the proboscis. Electron micrographs show that this fiber is composed of smaller fibrils. These smaller fibrils are attached to the kinetosomes of the feeding cilia on both the right and left sides of the larger fibril bundle. Thus, the mid-ventral fibril bundle lies between two ciliary rows and provides fibrils for kinetosomes on both its right and left sides. Therefore, it seems likely in the case of this gymnostome, that there exists an exception to the rule of desmodexy as postulated by Chatton and Lwoff (1935). The function of these fibrils remains obscure but it is suggested that, in view of their close association with the feeding cilia and the non-retractable nature of the proboscis, their function may be primarily coordinative. However, the possibility that they may also be concerned secondarily with minor contractions is not excluded.The armature of the cytostome-cytopharyngeal complex is composed of two distinct systems: (1) a system of fibrils which are apparently kinetodesmal and (2) a system of trichites. The fibrils are thought to be associated with the feeding cilia of the proboscis as well as with those which surround the cytostome. The fibrils extend into the cytoplasm of the armature and are intermingled among the trichites. The tri-chites are arranged in two concentric cones around the cytostome. In the outermost cone they are larger and arranged in almost single file as opposed to the smaller size and the more or less random orientation of those of the inner cone. They are composed of smaller hexagonally packed rods which measure 170-180 Å in diameter and are separated by a space of about 100 Å.

Notes: Of fragments involving a partial removal of the original adoral zone of membranelles (AZM), the monomacro-nucleate ones become reorganized monostomes resulting from a simple fusion of the remnant AZM to the oral primordium induced, and the binucleate ones become dividers by initiation of the oral primordium posteriorly from the posterior terminal of the remnant AZM. The cirral primordium in any fragment arises alongside its corresponding oral area. Weisz's idea of the dominance and inhibition of the original oral system extending over the oral primordium site is applicable in stomatogenesis of the present species. This application is found also in cirral formation.In fragments from early stage dividers, a formed oral primordium is easily absorbed by influence of the intact original AZM. This event also occurs after complete removal of the AZM. Such results led to the hypothesis that the oral primordium in the normal divider may be formed under some stoma-togenic activation of the AZM followed by escape from inhibition also arising from the same source. Irrevocable furrow formation and irreversibility of the oral primordium in stomatogenesis occur in later stages of division. Nevertheless division in these stages is blocked when certain operations are performed, forming monsters possessing the AZM of the opisthe translocated to the side opposite to that of the proter. In other monsters obtained from a fusion of the AZM of the proter to that of the opisthe, division occurs belatedly, prior to which secondary oral and cirral primordia are produced.

Notes: A new astomatous holotrichous ciliate, Radiophryoides puytoraci, parasitic in the gut of the Indian freshwater oligochaete is described. This is the second finding of the astomatous ciliate parasite from the microdrili from Asia. Key to all the known and valid species of Radiophryoides is given.

Notes: The in vivo absorption spectra of the chloroplast and eyespot of Euglena gracilis were obtained by microspectro-photometry. The average chloroplast absorption spectrum shows major peaks at 430-43S and 675-685 mμ. The fine structure details of chlorophyll à show peaks at 675, 685 and 695 mμ. The average eyespot absorption spectrum shows major absorption in the region of 460-490 mμ, and two additional peaks near 510 and around 530 mμ with lesser peaks at 430 and 630 mμ. Some of these same absorption peaks were obtained for the eyespot of E. granulata and the “hematochrome flecks.” The eyespot spectrum indicates that probably more than one ca-rotenoid is present and that a correlation exists between the eyespot absorption spectrum and the Euglena phototactic action spectra.

Notes: The incidence of Hepatozoon balfouri (Laveran, 1905) in examined populations of Egyptian jerboas was 41% in Jaculus j. jaculus, 21% in Jaculus o. orientalis, and nil in Allactaga tetradactyla. Infection in a few animals apparently less than 6 days old suggests the possibility of transplacental transmission. The cycle in erythrocytes and parenchyma cells of the liver is described; stages in liver are seldom seen in chronic infections. Blood of many other Egyptian rodents and insectivores was negative for H. balfouri.The sporogonic cycle in mites, Haemolaelaps aegyptius Keegan, 1956, fed on infected jerboas, resembles that of other typical Hepatozoon species. Sporocysts contain 6 to 16 (usually 12) sporozoites. Infection rates in experimental cultures of H. aegyptius varied greatly. Mites from only a single graphic area could be experimentally infected; in the same area, the infection rate in J. jaculus is significantly higher than elsewhere. Biological races of Haemolaelaps aegyptius, more or less refractive to H. balfouri infection, may exist. Large numbers of mites, lice, fleas, and ticks removed from infected jerboas were uninfected, as were numerous arthropods experimentally fed on infected jerboas.Owing to the presence of H. balfouri foci in widely differing ecological zones of North Africa and Sudan, different species of mites, and possibly of other arthropods, obviously transmit the infection; details of this likelihood require further investigation.

Notes: SYXOPSIS. The duration of photic suppression of plasmosol movement was used as a measure of the sensitivity of Amoeba proteus to selected wavelengths of monochromatic stimulation. Radiant energy was equated across the wavelengths which ranged from 420 to 620 millimicrons. The data generally confirm previous findings but indicate that maximum sensitivity lies in the green (515 mμ) rather than the previously held blue (450-490 mμ) region.

Notes: Frontonia microstoma, a ciliate living in brackish water, is described. The somatic infraciliature, the buccal in-fraciliature and the fibrillar buccal system show essential characteristics of species of Frontoniidae Kahl. The number and the arrangement of vestibular kineties are specific. Dark blue-green pigment is formed by small ectoplasmic vesicles. Formation of cysts is frequent in natural medium and cultures. There is no dedifferentiation of ciliates when encysted. Excystment is induced readily. Thriving cultures of F. microstoma have been obtained by feeding the ciliates with appropriate species of Cyanophyceae. Growth was better in brackish water than in either sea water or fresh water.

Notes: An amicronucleate clone of Tetrahymena pyrijormis has been found among the asexual progeny of irradiated cells of strain EU 6000 (variety 6, mating type I). Log-phase cells of this clone, designated EU 6525, have a mean generation time (6.0 hr) longer than that of the micronucleate strain, EU 6000 (2.9 hr). Further irradiation studies of strain EU 6000 indicate that the recovery of viable amicronucleate populations is rare although many amicronucleate cells are found among surviving progeny.1 Attempts to introduce micronuclei into amicronucleate cells of strain EU 6525 by conjugation have been made. Micronucleate lines are obtained from amicronu create pair members only in low frequency. These results, considered together with those of other workers, suggest that some change in the state of the cell, additional to the physical loss (or gain) of the micronucleus, must occur before viable amicronucleate clones can be obtained from micronucleate cells, or before amicronucleate cells can produce viable micronucleate lineages. An alteration in mean generation time may be a reflection of this change, or it may simply be a direct consequence of micronuclear removal. The results further imply that the ciliate micronucleus unquestionably contributes information to the cell during asexual growth and reproduction.

Notes: The chromosome cycle in the vegetative division of Euglena viridis was investigated. The seeming chromatin granules in the interphase nucleus are in reality thread structures, paired and very loosely twisted. Each component of the paired threads is called a chromatid, and consists of a fine thread of even thickness, the chromonema.In the prophase, linear contraction and thickening of the chromatids occurs by means of the spiralization of them. In the later prophase, the coiled chromonema splits into two finer strands which show the plectonemic spiral. At the metaphase, the chromosomes are arranged in the form of an equatorial ring, encircling the median portion of the elongated endosome. Nearly all of the chromosomes have a submedian or a sub-terminal and a few of them have a terminal kinetochore. In the early anaphase, separation of the sister chromosomes takes place beginning at the kinetochore. The spindle fibres in the metaphase and anaphase were not observed. The two stranded spiral in the chromosomes is separated into distinct components by the uncoiling in the later telophase, and they are transformed, in the interphase nucleus, into the paired chromatids.

Notes: Six strains of Entamoeba histolytica were studied in an initial attempt to define some genetic characteristics. Sugar metabolism and drug sensitivity were the markers studied. The six strains showed little difference in characteristics and attempts to obtain mutations have been unsuccessful. The observed characeristics may be useful in helping to define the species.

Notes: Oxidative assimilation of acetate by Euglena gracilis was studied using methyl- and carboxyl-labeled radioactive acetate. Of the total carbon utilized, 40% was oxidized to CO2 and 60% was assimilated; 20% of the CO2 produced was derived from the methyl carbon, and 80% from the car-boxyl carbon of acetate. Seventy % of the carbon assimilated was derived from the methyl carbon and 30% from the carboxyl. The results suggest that assimilation involves decarboxylation of Krebs-cycle oxalacetate and assimilation of the resulting pyruvate.In the presence of ethanol a greater proportion of the acetate carbon is assimilated, though the total acetate consumption is almost unchanged.

Notes: Induction of conjugation in clones of variety 7 of Tetrahymena pyriformis required more precise control than was necessary for the classical variety 1 clones, WH-6 and WH-14. Axenic methods are herein described which were successful in eliciting the mating response; especially important was a period of growth under optimal nutritional conditions, and use of animals in the logarithmic phase of growth.Three cases of presumptive age-induced selfing are reported, along with the discovery of new mating types III and IV. The isolation of a stage intermediate between a “pure” marine type and a selfing condition offers additional evidence for mating type instability. An analysis of the system of mating-type inheritance shows a pattern similar to that seen in Paramecium aurelia (Group B), and variety 9 of Tetrahymena pyriformis.

Notes: Ingestion of fluid by axenically cultured Tetra-hymena pyriformis requires an inducer, which can be provided by peptone-yeast extract broth. Cells in this medium contain many phagotrophic vacuoles; the formation of these is readily followed by allowing peptone-yeast grown cells to ingest the impermeable dye, trypan blue. Tetrahymena grown in synthetic medium contain only few vacuoles and do not ingest trypan blue to any significant degree. Addition of peptone-yeast medium to cells grown in a synthetic medium “induces” vacuolar formation and uptake of the dye. Calculations based on the rate of ingestion of trypan blue and of heat killed cells of Serratia marcescens indicate that the phagotrophic process cannot adequately supply the nutritional demands of the organism. Experiments using the colored amino acid analog, 3,5-dinitrotyrosine contrast the rapid penetration of material through the cell membrane with the more sluggish route of phagotrophy.

Notes: Histomonas meleagridis was successfully cultured without demonstrable bacteria in a modified tissue culture medium enriched by fresh hamster liver and metal ions.

Notes: The morphology and division of Entodinium dubardi dubardi Buisson 1923, found by the present writer in the rumen of a white-tailed deer (Odocoileus virginianus borealis) from the state of New York, are described. E. longi-nucleatum was found for the first time in this host. A transitional form of E. d. dubardi leading to E. d. cervi Sladecek 1946, was seen. Rotund or orbicular-like individuals occurring in the material are the postdivisional stages of E. d. dubardi. Comparative study of preparations from the mule-deer Odocoileus hemionis hemionis, O. hemionus Macrotis, and another white-tailed deer gave the same results as in the study of the principal host. Very close resemblance of the post-divisional stages of E. d. dubardi with E. bovis Wertheim and E. orbicularis Bush & Kofoid is noted. New data have been established to regard E. simplex Dogiel as a synonym of E. d. dubardi.

Notes: Disematostoma colpidioides von Gelei, 1954, is a Peniculina which stands out principally by a very markedly-twisted shape, resulting from the allometric growth of some of the right somatic kineties, and by the sigmoid curvature of the postoral suture. During the fission of the macronucleus, it is possible to observe the expulsion of a small chromatic mass which degenerates quickly. A part of the buccal apparatus undergoes a dedifferentiation during the encystment, so that the three “peniculi” disappear while the vestibulary kineties persist.

Notes: Most of the thigmotrichous ciliates of the family Ancistrocomidae are parasites of gastropod and pelecypod mollusks. The only known exceptions are Hypocomella pho-ronopsidis, from a phoronid, and some species of Hypocomella and Heterocinetopsis which parasitize the oligochaete Chaeto-gaster limnaei as well as certain of the fresh-water snails with which this worm is commensal. Two new species of marine ancistrocomids, found on the Pacific coast of Oregon, infect hosts belonging to groups from which ciliates of this type have not previously been reported. Hypocomella katharinae sp. Now is a parasite of the ctenidial epithelium of the chiton Katharina tunicata. Ignotocoma sabellarum gen. nov., sp. nov., is found on the peristomial cirri of two polychaete annelids of the family Sabellidae: Schizobranchia insignis and Eudistylia polymorpha. The genus Ignotocoma differs from previously described genera of ancistrocomids in having its ciliary system separated into two fields, each consisting of seven or eight rows, which are largely limited to weakly concave areas lying on opposite sides of a longitudinal ridge-like eminence on the inferior surface.

Notes: Bleaching (interference with chlorophyll accumulation) by streptomycin (SM) is more effective when dark-grown Euglena gracilis cells are exposed to SM in the dark for several days than when exposure of dark- or light-grown cells is exclusively in light. Cells are also bleached when exposed to SM while lacking both chlorophyll and chloroplasts (i.e., exposed to SM in the dark and subcultured to SM-free medium before transfer to light). Bleaching therefore involves inhibition of the formation of a plastid or pigment precursor, rather than breakdown of chlorophyll or interference with replication of mature chloroplasts. Bleaching by SM B prevented by addition to the medium of any of several fin cations, including Mg. Therefore it is proposed that bleaching results from chelation of Mg by SM. thus blocking a Mg-requiring step in chlorophyll synthesis. Disruption by SM of chloroplast structure and/or development is considered a secondary consequence of the bleaching action, resulting from the essentiality of intact chlorophyll molecules for normal chloroplast structure.

Notes: This second part deals with a subject analogous to the one developed in the first part, but related to surface irregularities with a non-cylindrical structure. In this part we have taken into consideration both the effects due to potential electrodes and the effects due to current electrodes.The study of these cases has been made with the help of mathematical theory, but it has been necessary to extend this theory from the case of cylindrical bodies to the case of non-cylindrical ones.Finally, as conclusion to both parts of the paper, some pages have been dedicated to the details of the calculation procedure, in order to demonstrate its practical htness for the study of this problem.

Notes: The usual computation methods in refraction seismic in the Sahara often involve considerable shot distances. Therefore, in addition to a high consumption of explosives, difficulties of operation and interpretation arise.In order to cut down the shot distances, it was necessary to study with great care the refracted waves having the shortest possible traveling path along the marker. Such paths correspond to the zone of great relative energy resulting, on one hand, from the sudden increase of reflected energy beyond the critical angle (total reflection) and, on the other hand, from the sudden appearance of refracted energy. The proposed method is founded on correlations of traces located in this “critical zone” on the different records shot on a profile; in order to get around certain difficulties due to insufficient knowledge of the marker velocity, the interpreter is led to select a constant correlation distance, at least for sections of the profile.The paper describes in detail the setting up and utilization of the proposed method, analyses a few examples and gives an estimate of the advantages and the restrictions of this method.

Notes: It was felt that Faust's first law was the best guide in classifying data concerning velocities and their correlation with lithology, even if, on a local basis, other laws fit the observed values better.Data have been re-examined which were provided chiefly by borehole measurements, both conventional and continuous, but also by some particularly reliable velocity profiles. “Faust's coefficient” has been computed for a series of geological formations, i.e. the ratio of true velocity to the value resulting from Faust's law, according to the age and present depth of the formation.Some graphs are shown, in the first place concerning the Sahara, and especially the Palaeozoic. It can be seen that the only formation showing values notably less than I disappears.On the other hand, values greater than I can be noticed for the quartzitic Ordovician of limited thickness.This comparison has been continued on a broader basis, using, in particular, data published by Faust and Wyrobek. The data concerning the very homogeneous Westphalian result in an average value slightly less than I.The Aquitanian basin has been studied in greater detail, owing to the closer spacing of the measurements.Generally speaking, the Middle and Upper Jurassic, the Cretaceous and the Eocene-Oligocene show values notably higher than the Palaeozoic in the Sahara. This seems to be connected with the higher proportion of limestones and dolomites. Values as high as 1.7 are observed in compact dolomites.Four maps are given, concerning the Oligocene, the Eocene-Paleocene (one of them excluding the Danian) and the Upper Cretaceous (exclusive of Danian), and a cross-section showing the link with lithology.Some discrepancies with regard to data from borehole samples are discussed.The question may be raised as to whether such studies can be carried out at the very beginning of exploration of a basin, on the basis of only a few logged wells. In the Aquitaine basin, data given by velocity profiles are in close agreement with those from wells as regards the Tertiary; but as regards the Mesozoic, information is meagre. In basins of the Sahara type, synthetic records have shown that interference of true and multiple reflections with each other is a major drawback. But on the other hand, the possibilities of a combined use of reflection and refraction in order to define lateral changes in velocities may not have been fully appreciated. Some computed examples are shown, since the results of a survey at present being carried out on this basis cannot yet be published.Finally, mention is made of the part played by the determination of anisotropy, and an appeal is made for more coöperation between geophysicists in this sphere.

Notes: The vertical component of the attraction exerted by a horizontal homogeneous polygon is obtained as the sum of terms proportional to the difference, for each of the vertices, between the external angle and its spherical perspective. A set of computation charts is presented, each for a fixed value of the angle of the polygon (22° 30′, 30°, 45°, 67° 30’ and 90°). These charts give the difference between the external angle and its spherical perspective as a function of the quotient of the distance from the sides to the vertical through the station over the depth. The chart for the right angle is an alignment chart, permitting a more accurate reading; the others are graphs in rectangular coördinates.For a remote station the result would be obtained as a small difference between relatively large quantities, and consequently with a not quite satisfactory precision. For these stations it is preferable to assume the entire mass to be concentrated in the centre of gravity.

Notes: It has been discovered that certain flowing oilwells in the Eakring area (Nottinghamshire, England), which have not otherwise been disturbed, show distinct annual variations in the flow of total fluid. There appears to be a definite connection between these variations and the seasonal movements of the earth's crustal layers as evidenced by observations of the tilts of the earth's surface. The investigation has been extended further to show that a similar relation exists between the earth tilts and the production of a whole oilfield which has not been disturbed unduly by outside influences.A correlation has also been established between the earth tilt observations and the periodicity of shallow earthquakes.

Notes: A method has been developed for the measurement, in the laboratory, of the variation of the elastic properties of rocks in the frequency range 40–120 cycles/sec. In addition, the observations yield information concerning the internal dissipation of energy over this range. A number of rock specimens have been examined and the results are compared with those of other investigators.

Notes: In the mathematical treatment of the propagation of seismic waves the process in the medium surrounding the point of explosion is introduced as initial condition into the differential equation. It is the purpose of this paper to contribute to the knowledge of this process.The treatment of the process of explosion is a difficult one because the elastic limit is exceeded in the surroundings of the point of explosion. To gain a better view on the acting forces the space concerned is replaced by a simplifying model. It is shown that a permanent deformation is caused by the explosion. This deformation will be especially intensive if the rock does not offer any resistance to tensile forces.To determine the extent of such a permanent deformation a sudden release of pressure — the opposite of an explosion — was recorded by seismographs. It has been proved that any seismic waves of measurable magnitude are not produced. This leads to the conclusion that permanent deformation plays an essential part in the generation of seismic waves.