278 



CESTODES. 



ducts and openings lie (Fig. 141) in the middle line, and are so 

 arranged that the openings are on that surface towards which the 



FIG. 139. Apex and hooks of Tcmia solium. 



FIG. 140. Head and anterior 

 portion of Bothrioccphalus cordatus. 



female ducts are approximated, while the male organs lie near to the 

 opposite surface. According to the analogy of the Trematodes, the 

 former must be the ventral surface, and the latter the dorsal; and 

 among the Tamiadae also there are forms which exhibit like conditions, 

 as, for example, the Tcenia litterata of the fox. As a rule, however, 

 the genital openings are shifted from the middle to the side walls, 



FIG. 141. Generative organs of Bothrio- 

 cephalus lotus (ventral aspect). 



FIG. 142. Generative organs of 

 Tcenia solium. 



and are found either all on one side, or on either side in an irregular 

 alternation (Fig. 142.) In such cases it would be hardly possible 

 to distinguish the dorsal and ventral surfaces, were it not that the 



