Prof. G. J. Allman on the Anatomy of Actzon. 157 
and terminating in culs-de-sac, where doubtless resides the fune- 
tion of elaborating the biliary secretion. We have just such an 
appearance as a careful preparation of glandular structure would 
present with all its component ducts and termimal cu/s-de-sac 
accurately disentangled ; we have in fact in the Phlebenteric sy- 
stem of M. de Quatrefages nothing more or less than an unra- 
veled liver. 
This view of the subject would appear to be admitted to a cer- 
tain extent even by M. de Quatrefages himself, who describes the 
blind terminations of the branches as surrounded with a layer of 
a peculiar substance which he believes to be the liver. Of the 
connexion of this substance with the gastric ramifications I can- 
not speak, as im Acteon I could find nothing of the kind. As 
M. de Quatrefages however has not succeeded in isolating it from 
the culs-de-sac, his statement amounts to an admission that on 
these terminations of the branches devolves the function of secre- 
ting the bile*. 
To the view now taken it may be objected, that the bihary 
ducts ought to open into the intestine behind the stomach. In- 
stances however of the bile beg poured into the stomach itself 
are by no means without example among the Gasteropoda, and 
in some cases, as in Scyllea and Onchidium, this secretion is 
discharged into the cesophagus. The remarkable partition of the 
liver in Onchidium moreover is an evident approach to the con- 
dition assumed by this organ in the mollusca now under consi- 
deration. Another objection to the hepatic character of the gas- 
tric ramifications may be urged from the curious discovery by 
Messrs. Alder and Hancock, that in Holis the extremities of the 
ramuli are not really ceeca, but open externally through the ter- 
minations of the branchial papillee. This however cannot be con- 
sidered as a valid objection. It is true that the termination of 
the ducts in culs-de-sac has been described as a universal con- 
dition of glandular structure, but it has been by no means proved 
that a perforate state of the terminations of these tubes is incon- 
sistent with the performance of the secreting function. The pur- 
pose served by this curious condition of the organ in Eolis it is 
not very easy to explain. I cannot however avoid looking upon 
the perforations in the extremities of the branchial papillz as 
analogous to the orifice placed at the base of the branchial plume 
* I have just seen an excellent paper on the anatomy of Eolis by Messrs. 
Hancock and Embleton (Annals, xv. pp. 1, 77), in which these gentlemen 
describe the terminations of the gastric ramifications in Kolis as lined by 
glandular structure, which in most species exhibits a complex follicular dis- 
position. The czeca in Acton are certainly much more simple, nor do they 
seem to be furnished with any distinct glandular lining. 
