CROW: TREMATODES OF KANSAS SNAKES. 127 



oesophagus are surrounded by glands. The intestinal cseca are 

 simple tubes, without lateral projections, extending to the be- 

 ginning of the last fourth of the body. The right tube is 

 slightly longer than the left. They lie in about the same plane 

 and follow the general body outline. They are generally round, 

 with an average diameter of .09 millimeter. 



The excretory vesicle is a Y-shaped tube, with very thin 

 walls — so thin that it can be traced only in sections. From the 

 small opening at the extreme posterior end of the body the 

 tube proceeds foi'ward, gradually growing larger till it reaches 

 the anterior end of the testes, where it divides, each branch 

 passing forward just inside its respective intestinal csecum 

 to about the posterior edge of the acetabulum. From the 

 bifurcation the crura grow rapidly smaller and terminate as 

 blunt points. At the widest point the vesicle measures .91 

 millimeter in width, while the dorsoventral diameter at the 

 same point is only .04 millimeter. At the neck, or just inside 

 the pore, the diameter of the thin cylindrical tube is .036 

 millimeter. The neck is surrounded by glands which define 

 its limits clearly. The position of the excretory vesicle is 

 dorsal to all the other organs except the yolk ducts. 



The testes are two very large oval bodies, situated in the 

 third fourth of the body, and nearly filling the body cavity 

 at its widest point. The left testis is slightly in advance of 

 the right one. They are the same size and measure .98 milli- 

 meter in length, .61 millimeter in width and .77 millimeter in 

 thickness. The vasa efferentia arise from the anterior surface 

 of each testis and pass forward dorsal to the uterus and to the 

 left of the ovary to the posterior end of the cirrus-sac, where 

 they join to form the vesicula seminaUs. The vasa are very 

 small tubes, .0098 millimeter in diameter, and can be seen 

 only in sections. The vesicula seyninalis is entirely within the 

 cirrus-sac, nearly filling it at the posterior end. In its course 

 it bends upon itself and is continued as a short pars prostatica. 

 The cirrus which follows is a large, long organ, and extends 

 through the cirrus-sac and outside the body wall a distance of 

 .528 millimeter. Its length within the cirrus-sac is about equal 

 to that outside the body. It measures .092 millimeter in 

 diameter. The cirrus-sac is a large organ enclosing the 

 cirrus, vesicula seminalis, pars prostatica and prostate glands. 

 It measures .363 millimeter in diameter at the widest point — 



