LYMNEIDH OF NORTH AMERICA. 187 
GenitTatia (plate X, fig. D): Male organs: Penis-sac cylin- 
drical, eight mill. long and two mill. wide, enlarging slightly at the 
distal end; penis very long (10 mill.) and gradually enlarging toward 
the head-end; the whole penis 1s somewhat club-shaped ; the penis-sac, 
as well as the penis, is made up of strong circular and longitudinal 
muscular tissue ; vas deferens very long (42 mill.) ; prostate duct rather 
short (10 mill.), not much dilated where it enters the prostate; pros- 
tate irregularly cylindrical, somewhat folded, contracted posteriorly to 
form a narrow, irregularly convoluted tube; retractor muscles two or 
three in number, one penis retractor and one or two penis-sac retrac- 
tors; protractor muscles numerous, six or more on the posterior face 
and one very large muscle on the anterior face, which is made up of 
about six smaller muscles. The muscles of the penis-sac show much 
variation in position (pl. XIV, fig. D), the posterior protractors being 
widely separated (2) oF close together and joined by small branches 
(1); there is normally one penis-sac retractor, but two may be present, 
as shown in figure 2. 
Female organs: Oviduct rather long, the convoluted uterine por- 
tion very large; receptaculum seminis very large, round, its duct ten 
mill. long, joining the oviduct two mill. from the vaginal opening ; 
albuminiparous gland of usual form; first accessory albuminiparous 
gland rather large, somewhat pyriform or roundly knob-shaped, its 
walls very thick; second albuminiparous gland very small, rounded. 
The organs are colored as follows: Penis, flesh; pemis-sac, black- 
ish; prostate, bright orange, receptaculum seminis, mottled flesh and 
yellowish ; albuminiparous gland, purplish and flesh ; accessory glands, 
light flesh; uterine portion of oviduct, yellowish and whitish. 
The peculiarities of the genitalia of megasoma are the shape of 
the penis and its size in relation to the penis-sac. The prostate also 
differs in form from that of any other species. The number and po- 
sition of the retractor and protractor muscles of the male organ are 
also noteworthy. The length of the vas deferens is equaled only by 
that of stagnalis. 
The genitalia of two specimens measure as follows (dissection No. 
23101): 
: Rec.  Pros- Penis Penis- 
: Penis- sem. tate Vas. re- sac re- 
Penis. sac. duct. duct. def. tractor. tractor. Shell. 
10.20 8.75 9.00 8.00 41.00 6.50 5.50 45.00 Canada 
10.00 8.00 8.50 7.10 44.00 5.00 5.00 41.00 z 
