The nudibranch family Dironidae. 531 
lobes are visible beneath the posterior lobes of the liver, resting 
upon the ventral intestinal loop, and forming the lower posterior 
portion of the visceral complex. They are all connected by ducts 
which .unite in a common slender hermaphroditic duct (Pl. 32 Fig. 20 
h.d) passing forward and upward to the anterior genital complex. 
Here the duct dilates into the hermaphroditic ampulla '(h.'«a) 
desceribing a double loop upon the posterior face of the complex, 
and, narrowing suddenly, bifurcates into the vas deferens and the 
oviduct. While the general arrangement of the anterior genital 
complex is the same for both species of Dirona, they present marked 
differences in detail. In Dirona pieta the hermaphroditic ampulla 
divides into a very long vas deferens (Pl. 32 Fig. 20 v. d) and 
a quite long and greatly dilated oviduct. The point of division 
(z) is in close apposition to the inner face of the mucusalbumen 
glands, but the oviduct is entirely independent of the latter 
at this point. It dilates into a roomy tube, as large as or 
larger than the hermaphroditic ampulla, and is coiled in several 
loops upon the lower anterior face of the anterior genital complex, 
opening into the inner portion of the genital atrium (Fig. 20 a). 
By this term is designated a cavity, crescentic in cross section, 
immediately within the external female opening. The tips of 
this cerescent are dilated and turned forward and upward. Fol- 
lowing the upper, dilated portion of this channel inward from the 
external opening, the mouth of a slender duct is found, leading 
into a small, scarcely dilated, blind sack, the spermatotheca, which 
lies upon the upper face of the genital complex. In Fig. 20 s 
this is represented as projecting freely above the albumen gland, 
and opening through the dorsal wall of the atrium. Just behind 
the opening of this duct is found the opening of the oviduct, 
and beyond and below that the opening of the albumen and mucus 
glands. The lower part of the crescentic channel corresponds to 
the duet of the accessory glands, and is undoubtedly the path taken 
by the egg band in oviposition, while the upper portion corresponds 
to the vaginal duct, occurring as a separate channel in other 
Nudibranchs. The almost rudimentary condition of the spermatotheca 
in this species is a very striking feature, and can scarcely be 
explained as a condition due to sexual immaturity. The dilated 
oviduct seems to have assumed in part the function of a spermato- 
theca, for it is frequently crowded with spermatozoa, while the 
spermatotheca itself contains relatively few. The examination of 
54* 
