408 Messrs. Alder and Hancock on a proposed New Orderr 
backwards and towards the right side, ends in the anus (i), which 
is median, and a little behind the centre of the body. 
At first we could scarcely determine the position of this organ, 
though we had traced the intestine almost to its termination ; 
and, notwithstanding that there is at this part of the back a 
swelling indicating its presence, yet there is no prominent nip- 
ple, and it is very difiicult to see the opening. The position of 
the anus however was made manifest by our observing excre- 
mentitious matter passing out of it, and its situation cannot 
therefore be doubted. We succeeded in gaining further proof of 
the position of this excretory orifice by using the compressor, so 
as to force the contents of the intestine through it. This w^as 
attained by placing the animal in the instrument wdth its dorsal 
ridge exactly in profile, and then adjusting the pressure, with 
great care, to avoid rupture. In this way we, more than once, 
forced out the contents of the intestine. 
Along each side of the back immediately below the skin, and 
distinct from it, is a v/ide, somewhat folliculated, and branched 
vessel (^, g, g, g), having the interior lined with a layer, more or 
less thick, of dark green granules. These vessels are joined to 
the sides of the upper surface of the stomach, which is nearly 
covered with the granular substance. In these vessels we think 
we perceive the true homologue of the liver of the more typical 
mollusks ; and in proof of this opinion we would refer to the na- 
ture of their contents, which, as just stated, are green and gra- 
nular. When these granules are highly magnified, each is found 
to be an aggregation of very minute corpuscules within a delicate 
membranous vesicle, having much the character of the micro- 
scopic structure of the glands of the papillie of Eolis. 
In Cenia and Acteonia the digestive system would appear to 
be similar to that of Limapontia ; both are furnished with a mus- 
cular buccal mass without jaws, but having a lingual apparatus 
formed as in Limapontia ; the hepatic organ has the same dispo- 
sition as in that genus ; and the anal aperture in both is indicated 
by a slight swelling on the median line near the centre of the 
back, though we have not determined its position in these two 
genera with the same precision as in Limapontia. 
This account of the alimentary system is very different from 
that given by !M. de Quatrefages in the description of his Cha~ 
lidis ccerulea. The anus and intestine he has altogether over- 
looked, and the two lateral hepatic vessels he has called the 
stomach, that organ having likewise escaped his observation : 
there can be no doubt, however, that C. carulea is as highly or- 
ganized as L. nigra. 
The Generative System lies immediately beneath the organs 
