2 00 Annals Entonwlogical Society of America [Vol. I, 



sa, the histological structure is similar throughout its entire 

 extent. The external peritoneal membrane covers a thin layer 

 of longitudinal branching muscles. Within these are the circu- 

 lar muscles which often run obliquely. Next within, is a layer 

 of epithelial cells with cell boundaries indiscernible, each cell 

 containing an ovoid nucleus embedded in a granular protoplasm. 

 The long axis of the nucleus is usually parallel w^ith the free ends 

 of the epithelial layer (Fig. 6, nep.) Within the lumen are 

 bundles of spermatozoa which are embedded in a secretion. 



Near the opening of the seminal vesicle into the glandula 

 mucosa the structure of the former differs from that just des- 

 cribed. The circular muscles are better developed, being from 

 two to three layers in thickness. The cells gradually increase in 

 size, cell boundaries are usually apparent and the nuclei assume 

 a position at right angles to the free ends of the cells (Fig. 3, nc). 

 These cells gradually pass over into the large cells of the glandula 

 mucosa (Fig. 3,0.) 



The openings of the seminal vesicles into the glandulae mucosae 

 are directed posteriorly towards the ducts of these glands. On 

 this account the sperms in passing from the seminal vesicles into 

 the mucous glands probably never reach the distal end of the 

 latter, but pass directly into the ducts of the glands and then into 

 the ejaculatory ducts. In all our sections we did not find any 

 sperms in the large swollen ends of the glandulae mucosae, a fact 

 which supports the above \'iew. 



Accessory glands: A transverse section through the accessory 

 glands shows that the epithelium is thrown into a number of 

 large folds which almost fill the lumen (Fig. 3). The epithelial 

 layer of the swollen distal part of the glands consists of exceedingly 

 long cells with cell boundaries usually well defined (Fig. 4). Each 

 cell contains a single ovoid nucleus with its long axis parallel to 

 the same axis of the cell. The position of the nucleus varies with- 

 in the cell; occasionally it is found near the free end, sometimes 

 near the middle, but more often the nucleus is found near the 

 basal region of the cell. These cells are glandular and contain 

 numerous droplets of secretion (Fig. 4, g). The epithelium .rests 

 upon a thin basement membrane, outside of which are the muscle 

 layers. Within the folds of the epithelial layer are branching- 

 muscles which are not so well developed as the external circular 

 muscles. External to the circular muscles is a ver^' thin delicate 

 peritoneal membrane. 



