DENTALIUM. 227 
points @appui to tun from side to side, and also to climb 
and secure its food from the stems of the foraminiferous 
polyparia ; the third or basal ‘section is a long flattish pedicle, 
deeply grooved on its upper and lower surfaces, extending to 
the base of the stomach, into which it opens, as it is hollowed 
out as far as the tenacular flaps, but there is no passage to 
the exterior surface. I have failed to discover the reason for 
this connection with the stomach: the hollow part is filled 
with water, but from what source does not appear, though I 
think it must come from the buccal aperture. The use of this 
singular structure is clearly to augment the flexibility of the 
foot, as the animal frequently and suddenly doubles it up as 
the elephant does its trunk; and also to withdraw the two 
anterior parts into the hollow portion: this retractile action 
is necessary in consequence of the peculiar mouth of the ani- 
mal and the rigid character of the anterior end of the mantle, 
to convey the sustentation captured by the tenacula into the 
cavity of the mantle within the reach of the very short folia- 
ceous cirrhi at the buccal orifice. From the foot an elastic 
fibrous riband runs, on each side of the body, to the posterior 
terminus, and affords the animal the power of greatly con- 
tracting and dilating that end of it, as may be seen by the 
creases of contraction, which in some degree give the ap- 
pearance of annulations. 
At the base, and above the pedicle of the foot,—if that sur- 
face of the animal is upwards which lies in the concavity * of 
the shell, and vice versd, m the convexity,—is inserted a distinct 
light yellow tubular buccal appendage, without eyes or tenta- 
cula, which can only be considered a kind of external ceso- 
phagus, and as regards its accessories and form, has no pre- 
tensions to be styled a head; it is encircled by about eight or 
ten short dendroid tentacular strands; its cavity forms two 
extremely dilatable pouches divided by a longitudinal septum, 
which become compressed and merge apparently into one at 
the poimt of passage into the stomach. These external re- 
ceptacles invariably contain from ten to forty, or even more, 
~* Concavity is dorsal, convexity is ventral. M. Deshayes states the 
contrary, but he is mistaken. 
Q2 
