1910.] ORGANS OF THE FISH CHIMERA M0NSTR0SA. 517 



greenish, due to its structure and contents. On dissection, the 

 cavity is seen to be partly divided up along the whole length of 

 the vesicula seminalis by thin connective tissue partitions, which 

 are regularly arranged and resemble the septa of an Earthworm, 

 in the anterior region. In the dorsal middle line, however, there 

 is a channel along which the products of the sperm-duct may 

 pass (text-fig. 42, a). 



In the green region the partitions gradually lose their orderly 

 arrangement ; they appear further apart and then present a 

 regular honeycomb on the inner face of the wall of the sperm- 

 vesicle. Whereas, too, the contents of the anterior white region 

 consist of closely packed spermatozoa along with some secretion 

 from Leydig's gland, the contents in the green region consist to a 

 large extent of the above secretion with spermatozoa scattered in it 

 (text-fig. 42, b). 



The posterior one-third of the seminal vesicle, beyond the 

 constriction, is thick-walled, and the partitions become again 

 repeated regularly, with a series of new partitions running at right 

 angles and in the direction of the length — the contents of the 

 compartments thus formed comprising free spermatozoa mixed 

 with the secretion of Leydig's gland. The sperm-duct, not 

 noticeable in the green region, now appears as a number of fine 

 inter-communicating ducts, into which the last six ducts from 

 the gland of Leydig empty (text-fig. 42, c). 



Histology of Sjwm- Ducts and Glands of Leydig. 



Sections through the above glands show them to be of uniform 

 structure throughout, viz., long coiled tubules of greater diameter 

 than the urinary tubules, the lining epithelium being columnar 

 and non-urinary, with much secretion containing nucleated 

 material in the lumen. These tubules are continuous with the 

 wider collecting tubes which pass across from the gland to the 

 sperm-duct or seminal vesicle, and which also contain the same 

 secretion as the tubules of Leydig's gland. 



No glomeruli are found in the gland. This fact I was able to 

 confirm by mounting thin pieces of the gland stained with 

 hsematoxylin and cleared in oil of cloves. This, no doubt, partly 

 accounts for the white appearance of the glands of Leydig as 

 compared with the brown kidney behind. 



The nature of the contents of the sperm-ducts and sperm- 

 vesicles was ascertained by transverse sections taken through 

 these structures in the regions marked I-YI in text-fig. 41, and 

 illustrated by text-figs. 43-48. 



Text- fig. 43 is a somewhat diagrammatic representation of a 

 section through region I of text-fig. 41. The sperm-duct is 

 much coiled and its cavity is filled with spermatozoa, mostly 

 free, although there is a tendency towards aggregation in some 

 of the coils. 



In region II Leydig's gland is larger and the sperm-duct no 



