GAMETOGENESIS OF SACCOCIRRUS 47 



Fig. 10. — Later stage. The mitochondria have begun to rim together 

 to form a number of larger sphei'es (mm). At X is one of the large granules 

 seen in fig. 9 and in PI. 1, fig. 2, while at Gx is the same body mentioned 

 in the description of fig. 9. The yolk-granules (y) form a fine group to 

 one side of the cell. The nucleus in this cell is still spherical, in this being less 

 advanced than that of fig. 9, which is depressed, ch.k. 



Fig. 11. — Later spermatid, nucleus now depressed on one side, or cap- 

 shaped. The macromitosomal spheres (mm), ' Nebenkern ' of some authors, 

 are larger, not all the same size, and there is still a collection of unused 

 mitochondria at m. The acrosome is seen as a thickened edge of the 

 nucleus at as. Other parts as before, except that notice should be taken 

 of the fact that the Golgi elements (ga) have become drawn up below the 

 macromitosomal spheres, ch.k. 



Fig. 12. — Later stage, all mitochondria have run into the macro- 

 mitosomal spheres (mm), only two of which are shown. Golgi apparatus 

 still drawn up below the mitochondrial spheres. The cytoplasm is stringy 

 as is often found in osmic-acid preparations. Nucleus further depressed 

 and shrinking in size, m.k., counter-stained in Altmann. 



Fig. 13. — Forming spermatozoon, showing elongated macromitosome 

 (mm) and other cell inclusions, ch.k. 



Fig. 14. — Macromitosome or mitochondrial spheres, at the stage of 

 fig. 12, but viewed from below. Note skeletal granules at x, and unequal 

 size of spheres, ch.k. 



Fig. 15. — Part of tails of fully-formed sperms, at a higher magnification 

 than in fig. 17, to show the bodies marked gax, which are thought to be 

 Golgi elements, m.k. 



Fig. 16. — Forming spermatozoon, at a stage later than that drawn in 

 fig. 13. 



Fig. 17. — Bundle of ripe sperms from coelom of male ; refer to fig. 15, 

 m.k. 



Fig. 18.— Receptaculum seminis of female, to show the presence of the 

 special granules (gax) on the tails of the spermatozoa, spz. m.k. 



Plate 3. 

 Oogenesis of Saccocirrus. 



Figs. 19 and 20. — Four oocytes prepared by the Mann-Kopsch-Altmann 

 method to show Golgi apparatus. The peculiar peripheral granules 

 derived from the sperm-tail (spt) arc shown well. At sp is the head of 

 the spermatozoon, and at nl a peri-nuclear thickening marking partly the 

 nucleolar extrusion, and also as well the peri-nuclear activity, which seems 

 to be something apart from nucleolar extrusion (note also PI. 4, fig. 35). 



Fig. 21. — A later stage showing Golgi apparatus and advanced nucleolar 

 extrusion, nl. The peripheral granules in such Kopsch preparations 

 appear to be of two sorts — those staining quite black, and those yellowish. 



