Pacific coast omgocii.kta. 14!) 



body-wall passes straight through the ctrloniic cavity to the anterior septa, which they 

 pierce immediately at the Ijase of the ovaries and testes (fig. 78). A double lumen 

 is seen only after it passci^ i)osteriorly to the ovary. The rosettes are not large, 

 hut I hick with a wide base; the latter is furnished, where it passes through the sep- 

 tum, with several small sac-like glands, each with a distinct lumen, which I followed 

 thi'ough the nuiscular layer of the spermduct and which T suppose empties into the 

 neck of the rosette (fig. 79). The rosettes are not enclosed in the sperm-sacs. 



Spenn-snoi. The three pairs of sperm-sacs are racemose, but not exceedingly 

 .so. There ai'e four or five large lobes of glol)idar shape seen in every section sus- 

 pended from the septum and on the under side of the intestine, tlKuigh somewhat 

 projecting above it. The two anterior sperm-sacs in x ami xi are smaller than the 

 posterior one in xii, the one in x being the smallest of tlie three pairs. Those in 

 X and xi are suspended from the anterior septum separating x/xi and xi/xii. Of the 

 position of the posterior sperm-sacs I am uncertain, but it appears suspended from 

 the posterior septum, the one separating xii/xiii, as far as I can judge from a cro.ss- 

 section. 



Spermatogonia. In the two anterior sperm-sacs the spermatogonia offered 

 nothing peculiar as regards the development of the spermatozoa. There is in each 

 sperm-sac a large central zone of peculiar cells, staining differently. They re situ- 

 ated very close together, and possessed in my preparation rather shrunken nuclei 

 (figs. 63 and 75). This zone exists iu all the various sperm-.sacs in the anterior as 

 well as in the posterior ones. The development of the spermatozoa in the two an- 

 terior pairs appeared entirely normal, the spermatogonia possessing the same form as 

 in other species, the large nuclei standing out freely like beads above the wall. But 

 in the posterior sperm-sacs the spermatogonia, one and all, looked quite differently. 

 They were here of many varying sizes, some small, some enormously large, and the 

 nuclei, instead of standing out from the wall of the spermatogonium, were always 

 bunched in the center, or sl:i'uug across it as a central band (75). In other spermat- 

 ogonia the nuclei were arranged as in a ring along the cell walls, but without pushing 

 out. When the nuclei were in the center there appeared always a row of large and 

 small vacuoles along the cell-wall. I find two sizes of nuclei, the smaller being al- 

 ways less in number, and about four times smaller than the large nuclei. When 

 counter-staiued with orange, the larger nuclei give quickly up part of their hsema- 

 toxylon, the smaller ones giving it up slowly and not at all. The cytoplasma of the 

 spermatogonia presented a very strong polarity as regai'ds its position, it being always 

 massed towards the cell-wall nearest the central germinative area (fig. 63). A some- 

 what sirailar^process of developing spermatogonia have been described by Vernon in 

 the ,spei*m cells of Bombyx. The central germinative cell in Bombyx appears to 

 correspond with the central area or cell agglomeration in Aleodrilus, but I have seen 

 no such budding out of the germ cells as figured by Vernon, but this may depend 

 on the insufficient material at my command. 



A large number of similar spermatogonia were found in very large numbers 

 in nearly all the anterior somites, either loose in the coelomic cavitv, or in a 



