Messrs. Hancock and Embleton on the Anatomy of Eolis. 89 



being placed chiefly on the right side, partially covered by the 

 stomach which dips down on the median line between them and 

 the posterior border of the buccal mass ; all their outlets leading 

 to a commoii orifice, which is situated on the right side between 

 the terminations of the rows of papillae and the margin of the 

 foot, and a short way behind the dorsal tentacles. 



This orifice exists at the depressed apex of a small conical nip- 

 ple or papilla, formed by a projecting and slightly puckered fold 

 of skin, and is readily seen. When this orifice is laid open, a 

 vestibule, or small cavity, is discovered, on the inner wall of which 

 are three perforations, two being easily discovered, surrounded 

 by a wrinkled and projecting border of skin, one directly in front 

 of the other ; a third may be detected with some pains among the 

 folds around the posterior opening, and at its anterior part. Of 

 the two openings first mentioned the anterior leads to the male 

 apparatus ; the posterior, which is the largest of the three, leads to 

 the female organs ; and the third, by far the smallest, leads to the 

 spermatheca. Such is the state of the external parts in their 

 most perfect state of contraction, after death, or in the absence 

 of sexual excitement during life. But during the breeding sea- 

 son it is often found that the vestibule is obliterated by the pro- 

 trusion outwardly of its inner wall, and then the anterior aperture 

 is replaced, as it were, by a curved conical projection with its con- 

 cavity posteriorly. This projection is the penis in a partial state 

 of protrusion, and directly behind the base of it is seen the large 

 female orifice, and immediately within this exists the third and 

 smallest opening. 



To obtain a complete view of the internal generative organs, it 

 is necessary to remove all the other viscera. The ovary, PI. III. 

 fig. 1 d, is then seen as before mentioned, filling nearly the whole 

 of the posterior part of the cavity of the body. It is of a pale yel- 

 low colour, lobulated and granular, broad and thick in front, ta- 

 pering behind. Its anterior surface is concave, and moulded upon 

 the parts directly in front. These are two large, delicate, semi- 

 pellucid, convex and somewhat rounded lobes of a gland accessory 

 to the female parts, PI. III. fig. ^- g g, which we will call the 

 mucus-gland, since it appears to secrete the mucus-like envelope 

 of the ova, as will afterwards be seen. 



These lobes are continuous with each other below, but above 

 there is a deep fissure between them running from behind forwards. 

 At the posterior end of the fissure lies the convoluted part of the 

 oviduct, fig. I /, which runs forwards into the fissure. Under 

 the convolutions of the oviduct lies the spermatheca with its duct, 

 fig. 1 hj i. At the anterior end of the fissure, and resting on 

 the front of the right lateral lobe of the mucus- gland, lies a long 

 pale-flesh-coloured much-convoluted tube, fig. 1 c, the testis, one 



