transversal. However, one must pay attention to the fact that a large part 

 of each plate is located in the anterior half of the clamp. In this connection 

 it is possible that these are the remnants of the anterior "lip" of Mazocraeidae; 

 however, the certainty of this is very doubtful. As regards our supposition 



O.lnn 



O.M 



Fig. 299. Hexostoma grossum (Goto), attaching clamps and its chitinous 

 parts. Explanation in the text. 



about the homology of the clamps of Hexostomatidae with the parts of the 

 capsule of Mazocraeidae, it is also substantiated by the plate -like make-up 

 of these formations. As a matter of fact, as is self-evident, special studies 

 on live subjects and particularly the study of early postembryonic stages 

 are indispensable for any final confirmations , whatever they may be. 



As regards the internal organization of Hexostomatidae, the p. 423 



greatest interest is aroused by the structure of the intestines, which obviously 

 acquired a most complex net-like structure secondarily. Only in Microcotyle 

 reticulata Goto apparently is there an analogous structure. However, in 

 this species one can also notice the basic trunks of the intestine throughout 

 a rather long extension. 



The sex system of Hexostomatidae resembles the one of Mazo- 

 craeidae as well as the one of Microcotylidae to an equal degree, and its 

 sharp asymmetry in the location of the beginning of both vitelline ducts and 

 correspondingly of the place of departure of the vaginal trunks can be con- 

 sidered as its only important difference. 



506 



