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The development of sperm from a spermatid in the scorpion, Centruroides vittatus (Say), is described. The mature sperm is short with helical nucleus and a peculiar structure of the sperm tail. This peculiarity consists of alternating mitochondrial derivatives and membranous or network elements wrapped about the flagellum. We note the absence both of microtubules in the sperm of Centruroides and also of the centriole adjunct, which is present in other scorpion spermatids.

The effects of spindle inhibitors and of protein synthesis inhibitors on segmentation mitoses allow us to classify them into six groups : 1. Colchicine type : destruction of the whole achromatic apparatus and centrospheres without storing of dense bodies; 2. Quinoline type : same effect on the achromatic apparatus, but blocked centrospheres with accumulation of dense bodies; 3. Chloralhydrate type : Incomplete destruction of achromatic apparatus, spindle residue which maintains the chromosomes in a star shape, inactive centrospheres sequestered by the reticulum, but without accumulation of dense bodies; 4. Phenylurethane type : Incomplete and reversible action, which leads to easy production of pluripolar mitoses; 5. Carboxylic acid type : dissociation of the spindle, sometimes with blocking of the centrosphere, together with profound chromosome changes without primitive breaks; the intensity and quality of their action is related to the number of carbon atoms in the acid considered; 6. Protein synthesis inhibitor type : (cycloheximide, pederin) characterized by a stop of the nuclear cycle at telo-prophase when the action is sufficient, chromosome abnormalities, sometimes, reduced to strings of beads, and freeing of asters; at weaker concentrations mitosis is possible, but the congression of chromosomes at the equator is abnormal because of functional disturbance of the kinetochores. The nature and grading of these effects, their association (or non - association) to chromosome damage, the soundness of the spindle when only the chromosomes are affected (nitrogen mustard) make this one of the tests which gives the most specific data about the action of antimitotic substances.

Nucleolo-cytoplasmic relationships have been studied in healthy squirrel monkeys and those subjected to a known degree of protein malnutrition. In the latter group, thirty-two pregnant animals starting from 35 days of gestation and 24 young adult animals were given a diet containing 7.5% and 2.0% protein content, respectively, compared to a diet with 25% protein for the controls. The motor cortex and the cerebellum removed from neonates as well as young adult animals sacrificed after 9, 11, 13 and 15 weeks of feeding schedules were investigated. Four animals after 15 weeks of dietary protein deprivation were rehabilitated with a balanced diet over a year's period. Formaldehyde-fixed as well as fresh frozen tissues were used for the histological study and to employ histochemical techniques for the demonstration of lipids, carbohydrates, nucleic acids and enzymes of various metabolic cycles. As a result of protein malnutrition, the nucleolus in a majority of the neurons from the motor cortex and the Purkinje cells of the cerebellum undergoes a series of morphological and cytochemical transformations in response to cytoplasmic changes related to impaired protein metabolism. The greater the level of protein deprivation, the greater is the degree of cytoplasmic chromatolysis and more pronounced are the nucleolar transformation in terms of enlarged size, secretory activity and transfer of nucleolar material in the cytoplasm. The nucleolar buds located close to the periphery of the nuclear membrane and the nucleolar material in the cytoplasm show identical cytochemical nature except for the presence of DNA in the former. It appears that during migration through the nuclear membrane the nucleolar material loses its DNA component and only aggregates of ribosomes and protein pass into cytoplasm, which aid in the synthesis of specific proteins lost as a result of catabolic processes initiated by protein malnutrition. Most of the observed changes in the adult squirrel monkeys are reversed when they are rehabilitated with a balanced diet.

The topography of Cochliatoxum periachtum is studied. The cuticle is very thick. The digestive, nuclear and excretory systems are located in the ectoplasm, they are not surrounded by the mesoplasm. The endoplasm is very large, it contains vegetable inclusions. By the features of its topography, this species is similar to some species belonging to the Family Ophryoscolescidae and, especially, to Eudiplodinium giganteum.

The digestive system of the Ophryoscolescides includes different parts : the adoral ciliary zone, the cytostome, the oesophagus, the endoplasm, the rectum and the anus. The endoplasm appears as a digestive sack surrounded by the mesoplasm. This fibrillary envelop separates it from the ectoplasm. It's in the endoplasm that the mechanism of the digestion develops. The endoplasm contains many different structures. It includes macrovesicles of three types, bacteria, plant-particles, microvesicles of two types, ergastoplasm, polysaccharides, the Golgi apparatus and fibrils. The macrovesicles of the first and the second type are not to be found simultaneously in the same endoplasm. The macrovesicles of the third type, very few in number, are different of the previous ones by their double membrane and their denser granulations. Large-sized vesicles contain bacteria at different stadia of digestion. At the end of the digestion, the bacteria are completely or partially degraded. The plant-particles ingested by the Ciliate are to be found in the endoplasm, surrounded by a vesicle. A first type of microvesicles are found in the oesophagus and in the rectum. They are distinguished by a deep black coloration of variable shape. Another type of microvesicles is also present in the endoplasm. They are small bright vesicles that can bud from large-sized vesicles. In the endoplasm the ergastoplasmic lamellae and rings are easily recognizable thanks to the ribosomes, that edge their external membrane. The ribosomes are also situated along the mesoplasm, around polysaccharidic grains and in small groups between the other endoplasmic elements. The polysaccharidic grains are netting-needle shaped bodies. Noirot-Timothee confers them a reserve function. The Golgi apparatus includes eight to eleven saccules. The extremities of those saccules present swellings or golgian ampullae. The endoplasm is also strewn with fibrillary structures that, cross-section are arranged in groups of four or five tubules. This type of endoplasm is found in Ophryoscolescides taken from a ruminant that has been fasting for several hours. In some individuals the endoplasm can have a totally different aspect. It is filled with vesicles of quite different sizes and shapes. The localization test of the acid phosphatase reveals, in this type of endoplasm, lead deposits. These vesicles are probably autophagic vesicles.

This study concerns the comparative development of gametophytes of nine Asplenium species. Some of them are diploïd, others tetraploid. They were studied on a cytogenetic point of view by british workers who found parental relationships between these species. The morphological analysis of the gametophytic development permits to determine the definite stages on which the tetraploïd species like to the supposed diploid parents. The inherited morphological characteristics are also described, for instance: formation of the prothallial plate, form of the marginal hairs. This qualitative analysis of the gametophytic development is not sufficient to confirm the supposed parental relationships. Therefore, precisions are given by the results of the quantitative analysis of the prothallial development and the study of the vascularization of the young sporophytes; these results will be soon published.

A precedent paper concerned a qualitative analysis of the gametophytic development in nine Asplenium species. By a quantitative study, we specify the parental relationships among these species. The surface of the gametophyte and the number of maginal hairs increase differently for each species. The density of the marginal hairs depends on the considered species. The relation among the morphological gametophytic parameters is constant in a group of determined species. The principal componant analysis is realized for all the parameters measured during the prothallial development. It confirms parental relationships among the diploids and tetraploids species on a morphological point of vue.

1. Karyotypes of 18 species of the sections Scutati (2), Vesicarii (2), Hastati (4), Afroacetosae (2) and Acetosa (8) of the genus Acetosa have been investigated in detail. 2. Four evolutive tendancies were distinguished i.e.: decrease of chromosome number and arm ratio, increase of chromosome length and differentiation of sex crhomosomes. These tendancies are fully expressed in the section Acetosa as compared with the others. 3. In this section, relationships between the subsections Acetosa, Insectivalves and Americanae were established especially dealing with the change of sex determination from the type XX/XY to the type XX/XY1Y2. 4. Evolutive pathways within the genus Acetosa as well as in the whole group of Rumex sensu lato are described.

In the cytoplasm of the ovocytes of Mytilus edulis, at the beginning of the yolk elaboration, but especially at the end of vitellogenesis, the polymorphous rough endoplasmic reticulum is very well developed. The concentrical disposition of the cisternae around of the mitochondria, the lipid inclusions and some granules of the yolk, are very frequent and must be considered as a system for increasing the area of proteic synthesis.

Fifty two taxa have been studied, out of which forty five, including the species; H. citrina, H. dumortierii, H. multiflora, H. forrestii and H. thunbergil are diploid with 22 chromosomes in the somatic complement. H. fulva var. Europa, H. fulva var. cypriana, H. kwanso "Flore Pleno" and H. disticha "Flore Pleno" are triploid with thirty three chromosomes in the somatic complement. One cultivar "Mrs. David Hall" is tetraploid with forty four chromosomes. Besides this two aneuploid clones "Garden Lady" and cv. "29" with 2n=23 and 2n=29 chromosomes respectively were also encountered. Essentially four basic karyotypes are recognizable; A(IV + 8L + 1J + 1I), B(IV + 7L + 2J + 1I), C(9L+ 1J + 1I) and d(8L + 2J + 1I), where V stands for median, L for submedian, J for subterminal and I for terminal centromere. Thirty two taxa could be relegated to these four types and 17 can be resolved as combinations of these four types. These fall under AB, AC, AD or BC, BD and CD classes. The number of nucleolar chromosomes does not show any correlation with the grade of ploidy, whereas 2, 3 or telocentric chromosomes were consistantly found in diploid, triploid and tetraploid taxa respectively. The possible origin of telocentric chromosomes and aneuploid taxa has been discussed.