164 



GUY C. ROBSON 



hepatic duct open into the stomach at its upper (posterior) 

 end. The pyloric part of the intestine and the style sac are 

 in open communication with each other, as in P. jenkinsi 

 (Eobson, 16), by means of a longitudinal slit for a considerable 

 way. Bregenzer does not refer to this as occurring in 



Text-fig. 3. 



Diagrammatic reconstruction of stomach to show relationship of 

 crystalline style sac. p, pylorus ; i, intestine ; st, style sac ; 

 I, hepatic duct ; o, oesophagus. 



Bythinella. No mention is made by Seibold of a style 

 sac in V i t r e 1 1 a , and, as his account is painstaking and 

 thorough, we have to assume that the sac is absent. This is 

 a very curious fact and one to which we shall return later. The 

 oesophagus and hepatic duct open into the stomach fairly 

 closely together. In this region the stomach epithelium is 

 ciliated, the ciliated area being continued dowTiwards and 



