534 



A DESCRIPTION OF THE ENTOZOA COLLECTED BY DR WILLEY 



The Reproductive System. 



One or two points in the 



Yftds 



Fig. a. Diagram of the reproductive 

 organs of Jilonostoiiutm trigono- 

 cephalum Rud. 

 Egg car. egg cavity, Gen. sin. geni- 

 tal sinus, Glds. glands at base of penis, 

 Ov. ovary, Sc. sucker, Sh. ghi. shell- 

 gland complex, Tl: right testis, Ut. 

 uterus, Vag. vagina, Vas. def. vas 

 deferens, Ves. sem. vesicula seminalis, 

 r. glds. yolk glands, .-1. rod-shaped 

 gland, B. dome - shaped organ, C. 

 glands opening into vagina. 



Reproductive System have hitherto been overlooked and 

 as the system is very complex I think a detailed description 

 will not be out of place. 



Male. The testes are two in number and lie at the 

 same level near the posterior end of the body (Fig. A)', and 

 as Walter points out their presence causes the forks of 

 the alimentary canal to bend in towards one another near 

 theu- posterior terminations. All stages in the spermato- 

 genesis can be seen in the cells of the testes. These organs 

 have no muscular walls and seem to lie freely in the 

 parenchyma. Each testis is roughly speaking spherical in 

 shape but the dorso-ventral muscles press into it in places 

 and thus in some sections it seems to be lobed (Fig. .5, 

 Plate LI v.). 



From each testis a short vas efiferens passes inwards and 

 forwards and verj- soon meets its fellow, and the two fuse 

 into a median vas deferens. This is as a rule filled with 

 spermatozoa. As it passes forward the vas deferens widens 

 and passes without an abrupt change into a capacious thin 

 walled vesicula seminalis which curves from side to side in 

 the most dorsal part of the body (Fig. A in text). The 

 vesicula is crowded with spermatozoa which as a mass 

 stain deeply, they are matted together like -ivisps of hay 

 and I could detect no head, nothing but a long tail. 



About half-way up the body the vesicula seminalis 

 passes into a very remarkable organ, which as far as I 

 can gather has not hitherto received much notice, possi- 

 bly it is only present in those specimens which are sexually 

 mature. Like the vesicula this organ i.s situated just 

 below the dorsal skin and it is median and unpaired. It 

 consists of a hollow rod-like gland with a well-developed 

 lumen (Fig. 4, Plate LIV.). Internally the gland is lined 

 by large cells which stain very deeply. The free ends 

 of these cells project like little balloons into the cavity 

 of the organ, and these swellings although ci'owded with 

 granules do not stain so deeply as the body of the cells. 



1 Looss states that "Die Hoden liegen bei meinen Exemplaren ausuahmlos asymmetrisch schrag hinter 

 einander, nur bei sehx stark contrahirten Thieren kommt gelegentlich der An sc he in einer symmetrischen 

 Lagerung zu Stande." 



I had no opportunity of observing the animals alive and my specimens had undoubtedly contracted, and 

 in them the right and left testes are situated at practically the same level. 



