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, which 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. can^estris, the organ which corresponds 
•to the penis of L. variegata becomes of a somewhat pro- 
