SPECIAL ANATOMY. £21 
is placed a ■white, calcareous, calcarate dart. At the 
junction of the vagina, common to the neck of the ovi- 
duct, duct of the generative bladder, and the dart sac, 
with the penis, there are two short retractor muscles 
inserted. The cloaca is narrow and cylindrical, and has 
surrounding two-thirds of its middle, a thick, glandular 
organ. Interiorly, the penis, cloaca, etc. have a longi- 
tudinally rugous surface. 
YagijS t ulus. A remarkable peculiarity of this genus 
is the removal of the male and female portions of the sex- 
ual apparatus from each other. The former, except the 
testicle and prostate gland, occupies the usual position, 
but opens externally between the mouth and olfactory 
orifice ; the latter is placed in the middle inferior part of 
the visceral cavity, and opens exteriorly on the right 
side, inferiorly just posterior to the middle of the body. 
The testicle is situated between the posterior part 
of the stomach and the liver, on the right side. It is 
not lobulated, but has the same aciniform arrangement 
as in the preceding genera. The epididymis is mode- 
rately tortuous, and becomes the vas deferens at the 
junction of the ovary with the oviduct. The vas deferens 
takes a remarkable course to get to the penis. It is, at 
first, attached for a short distance to the commencement 
of the oviduct, which it leaves, and then winds around its 
lower extremity, where it is joined by a comparatively 
very small prostatic gland. It continues its attachment 
to the lower part of the oviduct to the junction of the 
vol. i. 57 
