PLATYHELMIA 



55 



Solenocyte 



Each segment is hermaphrodite. Clumps of cells appear 

 first which are testes, and ducts arise in association with them. 

 These are vasa deferentia and culminate in a single coiled vas 

 deferens. This 

 opens to the exterior 

 on the side of the 

 segment on the pro- 

 jection containing 

 the genital pore. 

 Terminally the duct 

 is eversible in the 

 form of a penis or 

 cirrus. Two ovaries 

 are developed, the 

 ducts of which meet 

 and fuse. Just 

 after fusion the 

 oviducts receive the 

 vitellarian duct 

 from the yolk 

 glands, and at the 

 same place it is 

 surrounded by the 

 shell gland. Here 

 also it gives off a 

 diverticulum for the 

 storage of the eggs, 

 and this is called 

 the uterus. The 

 duct then passes to 

 the genital pore, or 

 atrium, where it 



Duct 



FIG. 25. Three solenocytes of the protonephri- 

 dium of Taenia crassicolis of the cat, after 

 Bugge and Meisenheimer. The solenocytes 

 have each a nucleus, the cytoplasm sends 

 amoeboid processes into the mesenchyme 

 spaces, and each of the cells is formed into a 



long tube which bears above a tuft of cilia 

 and is continued below to form the beginning 

 of the excretory duct. The fourth nucleus is 

 that of the cell forming the collecting duct. 



opens close to the 



opening of the vas 



deferens. There is 



reason for believing 



that this last part of the duct corresponds to Laurer's 



canal of the Trematodes, and that the uterus is the original 



oviduct which has lost its external opening. The sperms are 



