LYMN-EIDZ OF NORTH AMERICA. ial 
MALE orGans. The penis-sac (13) is very large, cylindrical, rather 
wide at the external opening and gradually contracting at the distal 
end where the penis is attached; it is grooved along its upper surface 
where a part of the prostate gland and the receptaculum seminis fit 
against it in their natural position. The penis (17%) is variable in 
length but is always a tube-like body about the diameter of the vas 
deferens and terminating in a more or less rounded head. The penis 
and the upper portion of the penis-sac are bent back upon the latter 
at right angles. The vas deferens (14) is a narrow white tube of vary- 
ing length; in its natural position it lies in two loops which run longi- 
tudinally with the penis-sac; at the right side of the penial aperture 
it enters the muscular tissue of the body wall where it runs in an irregu- 
lar course and emerges near the vaginal aperture as the duct of the 
prostate (31); this duct makes a long loop between the penis-sac and 
the proximal portion of the oviduct; as it nears the prostate it enlarges 
somewhat and enters that organ in a central depression. The prostate 
(30) is usually a somewhat sac-like organ, flatly cylindrical and lies in 
a groove on the posterior portion of the penis-sac. The oviduct and 
the duct of the spermatheca pass over its inferior surface in a groove; 
the first accessory albuminiparous gland lies below it and the recep- — 
taculum seminis lies posteriorly to and covers a portion of it. The outer 
surface is very rugose and the interior is divided into many small 
tubes. The posterior portion of the prostate (29) narrows to form 
a ribbon-like organ, often called the male portion of the hermaphro- 
dite duct. This portion connects posteriorly with the oviduct, with 
which it unites to form the ovisperm duct. 
The penis-sac is protracted by two sets of muscles, one of which 
(anterior, 15) is attached to the dorsal wall of the fore part of the 
body, while the other (posterior, 16) is attached to the columella 
muscle. There is a penis-sac retractor (19) anda penis retractor (18) 
which have their insertions in the columella muscle. The male sys- 
tem is innervated by a nerve from the cerebral ganglion which con- 
sists of two branches, one extending to the head of the penis while the 
other innervates the penis-sac. The penis-sac is a large tube with 
muscular walls, somewhat corrugated within, where there are also one 
or two distinct folds (plate IV, fig. H). 
FEMALE ORGANS. The oviduct begins at the ovisperm duct where 
it becomes much convoluted to form the so-called uterus (27). The 
point of its commencement is underneath the anterior end of the 
albuminiparous gland. Near the second albuminiparous gland it be- 
comes smooth and rounded (26), is later embraced by the large first 
