354 BENEDICT. [Vol. XVI. 



the anterior, and spreads out in all directions, increasing in size 

 with the development of the proglottis. The uterus spreads 

 first over the dorsal portion of the space, which contains the 

 sexual organs, and when fully developed occupies nearly this 

 entire space, with the exception of the rudiments of other 

 sexual organs. The branches of the uterus are few, and vari- 

 able in size and form. The tissue remaining is in the form of 

 thin partitions, which stand out perpendicularly from the side. 



The shell gland is more compact than that of most of the 

 Proteocephali, and extends equally on all sides of the ootype. 

 It appears as an irregular granular mass, with scattered nuclei 

 distinguishable within it, and large glandular cells grouped 

 irregularly in the outer portion. No trace of collecting tubules 

 can be distinguished, and the fibrous appearance indicates a 

 process to the ootype from each cell. This shell gland is much 

 larger and more compact than that described in any other species 

 of the genus (PI. XVI, Fig. 12). 



The vitellarian ducts occupy the lateral margins of the pro- 

 glottids, just within the longitudinal muscles and partly encir- 

 cling the nerve (PI. XVI, Fig. 9, vt.gl.). Two large ducts run 

 from the anterior portion toward the posterior end of the pro- 

 glottis. Numerous branches of various sizes join them in their 

 course. About the level of the anterior margin of the ovary 

 the main duct on each side curves inward and passes along the 

 dorsal wall until it is over the ootype ; here the two unite to 

 form the first vitellarian receptacle (PI. XVI, Fig. 10, vt.r.). Such 

 a union of the yolk ducts from the two sides seems to be a 

 characteristic of the genus ProteocepJialus. Riggenbach ('96) 

 describes such a condition in the forms he has studied, and 

 says that only in P. filicollis do the ducts enter the ootype 

 separately. P. filicollis, however, is not an exception, as my 

 own work has proved that the ducts unite exactly as in 

 P. amb lop litis (see p. 364). 



There are many variations in size, and some in the number 

 of these ducts ; there may be two from one side and only one 

 from the other, or those from one side may be very large, while 

 the others are narrow. The yolk cells are spherical masses 

 containing small, densely staining globules. 



