DISCODORIS BRANNERI MAC FARLAND 77 



uniform diameter of 0.7 mm. It is grayish white in color, and is 

 densely packed with spermatozoa. 



The wall of the hermaphroditic ampulla consists of a one- 

 layered low epithelium, resting upon a thin subepithelial layer 

 of connective tissue, which is in turn enveloped by a thin non- 

 continuous layer of circularly disposed smooth muscle fibres. A 

 loose connective tissue adventitia, not distinctly separated from 

 the muscularis, forms the outermost layer. In places the whole 

 wall is so reduced in thickness that it seems to be composed of 

 the epithelium alone. 



At the rounded posterior end of the nidamental gland the 

 distal end of the hermaphroditic duct passes into the connective 

 tissue along its anterior border, opening into a rather large cavity, 

 0.08 mm. in diameter, which is continued forward in the substance 

 of the gland for some distance. Immediately after entering the 

 nidamental-albumen gland complex the slender spermatic duct (PI. 

 XIV, figs. 73, 74, sp. d.) is given off, which, after its emergence 

 from the gland, passes almost immediately into the substance of 

 the prostate gland. These relations were made out in serial 

 sections only, owing to the minuteness of the structures involved. 

 It is of interest to note that the dense mass of spermatozoa, with 

 which the hermaphroditic ampulla was filled, did not extend into 

 the spermatic duct at all, but were confined to the extension of 

 the ampulla into the nidamental-albumen gland complex. 



Prostate gland. The prostate gland envelopes a U shaped 

 loop of the vas deferens (PI. XIV, figs. 73 and 74, pr. g.). It is 

 2.0 mm. in length, i.o mm. wide, somewhat prismatic in form, 

 approximately triangular in cross section, its surface smooth and 

 marked off into small lobules. Its posterior inner margin is 

 curved, its inner and ventral surface convex, while its anterior 

 distal portion is prolonged into two pointed lobes which inclose 

 a portion of the spermatotheca. It is enveloped by a very delicate 

 capsule of connective tissue covering the closely packed lobules 

 of the gland. The lumen is a more or less U shaped cavity, the 

 walls of which are formed by a single layer of cubical to columnar, 

 ciliated cells, passing over at the upper extremities of the U into 

 the ciliated columnar epithelium of the vas deferens, and the 

 spermatic duct respectively. Into this cavity open at intervals the 

 very short branched tubular glands which make up the bulk of 



