. MR. A. HANCOCK ON THE ANATOMY OF DORIDOPSIS. 197 
gland, made up of a dense mass of convoluted tube. This enormous development can only 
be explained on the supposition that the tube is not a mere vas deferens after all, but is, 
moreover, a gland ; and as it is not for the evolution of the spermatozoa, which we have 
seen are matured in the sacculi in connexion with the ovary, it is probably for the 
purpose of providing some fluid required only during the act of coitus, to be secreted 
in large quantity during a limited period of time. In the bulky and frequently much 
convoluted mucous gland in connexion with the female channel, we see another example 
'of an organ which has to elaborate its secretion during the short time required for the 
deposition of the ova. Hence the great development of these parts of the organism. 
The great mucous gland (Pl. XVIII. fig. 29) appended to the female organs is a large, 
elongated, rounded mass, somewhat lunate or bilobed,—the whole being of a yellowish 
colour, and more opake than usual. The posterior lobe is seen to be composed of a 
eonvoluted tube; the structure of the anterior portion was not determined, but the 
surface of the whole mass is minutely granular. The female channel (e) passes from the 
right or convex side of the gland, and is a short, thick tube. It opens externally 
immediately behind the orifice leading into the androgynous apparatus. A small compact 
gland (f), with follieulated walls, lies on the upper surface of the channel, and opens 
into it close to the external orifice. This is also apparently a portion of the female 
organs, though it may, perhaps, be functionally connected with the common vestibule 
into which all the parts open. 
The Androgynous Organs.—The tube (Pl. XVIII. fig. 27) leading to these organs we 
have seen to open into the common vestibule immediately behind the male intromittent 
organ, and consequently between it and the orifice of the female channel. It is very 
slender, corresponding in size to the penis which it has to receive during coitus, and is 
considerably longer than the female channel, over the surface of which it takes an undu- 
lating course. The outer extremity opens into the apex of a small conical pouch ; or 
rather the extremity may be said to enlarge a little at its termination. The other or 
inner extremity opens into the narrow end of a pyriform spermatheca (m), of a yellowish 
hue, which is fully one-third as large as the mucous gland. Close to the point where 
this androgynous organ receives the external or vaginal tube, it gives off a small duct (7), 
which shortly sinks into the mucous gland, near to the female channel, on its way to 
join the oviduct. Just before it disappears, it is joined by a short tube from a small, 
oval, rose-coloured sac or accessory spermatheca (0). 
The reproductive organs of Doridopsis mgra strongly resemble those just described. 
The male intromittent organ, however, is still more minute ; and the vas deferens, though 
divided into a dilated and attenuated portion, is much shorter than in the former species. 
The dilated portion (Pl. XVIII. fig. 3c) is of a pale yellow colour; and the convolutions 
of the minute tube within it are distinctly seen through its walls. 
The ovary is of a yellow colour, and is more extensively spread over the liver than it 
Sm D. gemmacea. The oviduct (h) is much attenuated ; it is short, and passes directly 
from the anterior portion of the ovary to the mucous gland (g), placed at the right side 
in the body. Just as it reaches this organ, it has appended to it we elliptical sac (7) of 
Considerable size, which is adherent, by the greater portion of one side, to the duct. This 
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