96 NICHOLS — SPERMATOGENESIS OXISCUS ASELLUS LINN. LApriU, 



C spermatoblaste ") were observed surrounding a protoplasmic 

 stem and their origin referred to the small cells in the apical por- 

 tion of the caecum. The structure of the nuclei and the changes 

 in them and in the surrounding protoplasm, by which the mass is 

 converted into the mature ''spermatophore," are described at 

 some length and illustrated with numerous figures. The name 

 ^'spermatophore " is applied for the following reasons: " Les 

 cellules spermatozoides sont done contenus dans un etui resistant 

 derivant de la differentation du protoplasm, c'est-a-dire dans une 

 production particuliere, on pourrait done appliquer aux faisceaux la 

 denomination de spermatophore." The name '^plasmodium 

 parietal " is applied to the follicle cells and the surrounding proto- 

 plasm, and to it is ascribed the function of taking part in the 

 formation of the tails, thus reinforcing the insufficiency of the pro- 

 toplasm of the germ cells. The tails of the spermatozoa are thus 

 thought to arise in the plasma and to attach themselves to the 

 nuclei ^' vers le haut." The exact level is not determined. The 

 form of the spermatozoa is compared to that of a whip, the long 

 tail representing the handle and the nucleus the lash. This would 

 seem to indicate that the tail is conceived as being attached to the 

 nucleus at its upper extremity. The entire bundle is said to 

 measure 0.15^0^ mm. 



The sheath (etui) enclosing the spermatozoa is most evident at 

 the anterior end. The apparent absence of protoplasm around the 

 filamentous nuclei is explained as perhaps due not to degeneration 

 or absorption of the protoplasm, but to a condensation and fusion 

 with the nucleus, perhaps applying itself so closely to the filament 

 that an effect of refraction communicates to it the same coloration 

 This hypothesis is based on results obtained by treating the flagellae 

 with nuclear solvents. When submitted to the action of potassium 

 carbonate in concentrated solution or strong hydrochloric acid for 

 several days the filaments become scalariform ; a skeleton formed 

 of little chambers is seen which communicate with each other, and 

 which were previously filled with the nuclear substance. The char- 

 acteristic frayed appearance of the bundles is thought to be due to 

 artificial rupture. 



The nuclear flagellae are said to grow considerably after having 

 attained their distinctive form. From the figures given to show 

 this (Figs. 329 and 330, PL VIII), it seems probable that this 

 appearance may be due to a portion of the filaments having been 

 broken off by teasing. 



