218 INTRODUCTION. 



has the appearance of being composed of rounded acini. 

 In L. variegata, it is lobulated. The epididymis is an 

 undulated, or moderately tortuous tube, leading from the 

 testicle to the inner side of the junction of the ovary with 

 the prostate gland. It opens into a groove upon the inner 

 side of the interior of the oviduct which is continuous, at 

 its inferior extremity, with the vas deferens. Opening 

 into the termination of the epididymis, and lying against 

 the inner side of the ovary, is a small, compound, folli- 

 cular body, Avhich appears to be common to all the terres- 

 trial Gasteropoda. The prostate gland is a white, or 

 cream-colored body, occupying the inner side of the whole 

 length of the oviduct. It has a transverse, striated ap- 

 pearance, and numerous openings into the groove leading 

 from the epididymis to the vas deferens. 



The vas deferens is a comparatively short tube, pass- 

 ing from the prostate gland to the penis. In L. varie- 

 gata, it joins the summit of the latter ; in L. agrestis 

 and L. campestris, it enters near the base. 



The penis, in L. variegata, is a long, cylindroid, irre- 

 gular body, lying at the right anterior part of the vis- 

 ceral cavity, and joining at its termination a short cloaca. 

 Into its summit is inserted the retractor muscle, which 

 has its origin from the muscular investment of the vis- 

 ceral cavity, just posterior to the position of the pulmo- 

 nary cavity. The interior of the penis is lined by mucous 

 membrane, its exterior of muscular membrane. In L. 

 agrestis and L. cajnpestjis, the organ which corresponds 

 to the penis of L. variegata becomes of a someAvhat pro- 



