CAECUM. 329 
extremity fixed im the hollowed-out chamber of the terminal 
process of the shell; it then extends to the stomach, accom- 
panied by the liver in alternate transverse portions; this 
organ is a light greenish mass formed of larger granules than 
the ovarium, and the contrast in colour of the two substances 
caused them to be observed without difficulty. 
The neck admitted of a close examination, and did not 
exhibit the slightest traces of external reproductive organs; it 
would therefore appear that the animal must depend on its 
own influences; however, there are doubts; and from the 
concordance of all its organs with a large class of the Pectini- 
branchous Gasteropods, it may, like them, be unisexual, though 
the organs have escaped detection. In all the specimens 
examined the ovarium was present in the usual place, and in 
no instance appeared to be replaced by the testicle; but the 
discriminations of such minute organs cannot be depended on. 
The foot is short, narrow, and truncate anteriorly when in 
action, sloping posteally to an obtusely pointed or rather 
rounded termination, on the upper part of which end is fixed 
the strong, circular, corneous, black-brown operculum, smooth 
and conical on the surface attached to the foot, concave with- 
out, and from its centre seven or eight fine close-set spiral 
lines, not concentrical, fill wp the area. 
The animal is not at all shy ; it shows itself in all directions. 
The generic term Cecum appears to be somewhat objection- 
able in point of significancy. On the discovery of the animal 
I proposed to my friend Dr. Goodall, the late Provost of Eton, 
the generic appellation of Dentaliopsis ; but Dr. Fleming is in 
possession of the field, and has the undoubted priority, and 
I may say, owing to my own neglect, in not launching the 
genus : 
SHOSiEP0. 6.4.7, feci, tulit alter honores.”’ 
C. cuasrum, Montagu. 
C. glabrum, Brit. Moll. ii. p. 181, pl. 69. f. 5. 
After a research, in which I almost despaired of success, I 
had the good fortune to meet with two living vivacious speci- 
mens of this species in the coralline zones of the Devonshire 
