208 MR. R. OWEN ON THE ANATOMY OF THE CALYPTRAID. 
This internal cup is received in a deep fissure of a corresponding form on the dorsal 
aspect of the body of the animal. Its cavity is filled by what may be termed the apex 
of the foot, which here loses its muscular character and assumes a gelatinous texture : 
the ovary, liver, heart, and loop of intestine are lodged in the recess between the cup 
and the outer shell. The margin of the mantle is free in the whole of its circumference, 
and is generally in the contracted state folded upon itself, as in Plate XXX. Fig. 4. 
The entrance to the branchial chamber is above the head, as in the Pectinibranchiata, 
and opens towards the right side, but is not prolonged into a siphon. In Calyptrea 
Sinensis, Lam., (the species dissected by M. Deshayes,) this chamber is continued along 
the left side only of the body; but in Calypeopsis, where the internal plate is cup-shaped, 
the branchia and its pallial receptacle are prolonged round to the right side, describing 
a complete circle. The foot, which in Cal. Sinensis is of a simple circular form, is here 
provided with two thin aliform expansions continued from its anterior margin : the rest 
of the foot is of considerable thickness, and is separated from the mantle by a fissure. 
The head, the mouth, the unretractile tentacles,—a single pair, with the eyes at the 
outer side of their base,—the neck, and its lateral expansions, present no deviations 
from the structure of the same parts as they exist in Crepidula! and in Cal. Sinensis. 
In the males (for the Calyptreide are incontestably dicecious, like the higher Pectini- 
branchiata,) the penis, a long filiform organ, extends from the right side of the neck, 
just below the tentacle. In some female specimens a small production of the cervical 
ala extends from the corresponding part, simulating, as it were, the intromittent organ 
of the male. 
The tongue is a semiorbicular body, with a free anterior margin, and supports a long, 
narrow, horny, laminated plate, or rasp, similar to that of Cal. Sinensis, and capable, 
doubtless, of being protruded externally, as in other Mollusks. The esophagus is long 
and narrow ; it begins to dilate into the stomach at the lower part of the neck, and it 
is just anterior to this dilatation where it is surrounded by the nervous collar. Anterior 
to this collar, the neck on either side of the esophagus is occupied by two elongated 
unbranched salivary follicles, with glandular parietes, which open into the wsophagus 
on each side the base of the lingual plate. I have found the same salivary apparatus 
in the subgenus Crepipatella, which, in the form of the internal plate, resembles Cal. Si- 
nensis. The genus Clio among the Pteropods presents a similar simple form of the 
salivary apparatus, but in the Whelk (Buccinum), and other dibranchiate Pectinibranchiata, 
the glands assume the conglomerate structure. The globular stomach is surrounded 
by the granulated liver, and receives the biliary secretion by many orifices. The in- 
testine is continued a little way down the left side, and after penetrating the ovary in 
1 Cuvier, loc. cit. 
