148 



part, which is approximated to the penial lumen, stains lightly. At 

 the ventral side of the bulb the cells merge gradually into the hypo- 

 dermis of the body wall. The sperm duct meets the dorsal part of 

 the bulb near the lateral body wall, and unites with the bulb in such 

 a way that the terminus appears to be imbedded in the periphery of 

 the bulb. In most cases this union is nearest the posterior part of 

 the bulb. There is no differentiation between the sperm duct and the 

 penial lumen, and it is a little difficult to determine the exact junc- 

 tion of the two. As the junction of the sperm duct with the bulb is 

 slightly posterior, the penial lumen follows a cephalo-ventro-lateral 

 course in reaching the exterior. The cuticula is reflected into the 

 penial lumen and lines it for its entire length. 



Spermathecce. — A pair of these organs (PI. IX, Fig. i6) is present 

 in V. There is no well-defined line of separation between the duct 

 and the ampulla. The ectal opening has a well-developed crown gland 

 showing a series of emarginations on the ental margin, which gives 

 it the appearance of having about six lobes. This gland is large 

 enough to completely hide the spermathecal duct, since the ental 

 periphery of the gland extends to the ampulla. The duct gradually 

 merges into the ampulla, a fusiform region constituting the greater 

 part of the mass of the spermatheca. The ental region of the ampulla 

 gradually becomes reduced in diameter, forming a sort of duct-like 

 terminus which has approximately the same length and diameter as 

 the spermathecal duct. This ental part of the ampulla bends cephalad 

 and unites with the digestive tract. This union is lateral in position 

 and exactly opposite the corresponding opening of the other sperma- 

 theca. An examination of sexually immature specimens shows that 

 the spermatheca lacks connection with the digestive tract, — a fact 

 which seems to point to the conclusion that the ental part of the am- 

 pulla is the last part to be acquired by the developing spermatheca. 

 The ectal opening of each spermatheca is surrounded by a thickened 

 region of the hypodermis. 



The abundance of material and its perfect histological condition 

 has made it possible to study in some detail the histology of the sper- 

 mathec?e. A number of interesting structural features are present and 

 seem worthy of extended discussion, since the meager treatment of the 

 structure of the spermathecre in species of Luinhricillus gives no hint 

 as to whether the condition in this species is unique or common to the 

 group. 



The wall of the ampulla (PI. IX, Fig. 23) is composed of three 

 layers, the enveloping peritoneum, the muscle layer, and the lining 

 epithelium. The peritoneum is of the usual type, being merely a thin 



