114 
CATALOGUE OE CEPHALOPODA. 
B. Shell apex enveloped in a thichened laminar Coat , more or less 
produced behind. 
2. Spirulirostra. Apex of shell spinal. 
3. Beloptera. Apex of shell nearly straight. 
Munster has given a genus under the name of Corniculina , type 
C. Elirenbergi but it wants further examination ; see Broun, 
Gesch. der Nat. iii. 535. 339. 
A. Shell thin ; apex hooked , not enveloped in a thickened laminar 
Coat. — Becent. 
1. LXTUUS. 
Body oblong, rather compressed. Mantle free, upper end trun- 
cated, with a projection of the margin on the middle of the back, 
and one on each side of the siphuncle on the ventral side. Fins 
two, small, caudal on the side of the extremity of the back. End 
of the body sometimes furnished with a central, rounded, thick- 
ened belt, with a central rounded cavity. — Head rather com- 
pressed ; eyes large, covered with the skin. — Sessile arms 
triangular, tapering, rounded externally ; cups numerous, equi- 
distant, very small, slightly pediceled, in six longitudinal series ; 
rings entire, or very minute, denticulated ; third and fourth 
shortly webbed, the rest free. Tentacular arms elongated, 
cylindrical; club ?. — Siphuncle with an apical 
valve. — Shell calcareous, cylindrical, conical, tapering, involute 
on the same plane, the whorls separate from each other, cham- 
bered. Septa concave outwards, with a shelly funnel-shaped 
siphon on the inner or most curved side, traversing each cell 
without communicating with each other. Last chamber rather 
the largest ; the nucleus, or first-formed chamber, roundish, 
swollen, embedded, placed symmetrically, the larger portion being 
on the hinder part of the centre of the back, and the smaller 
whorls below on the hinder part of the ventral surface, covered 
on the sides by the flesh of the body, and above and below by a 
thin skin. 
Feron and Lamarck represent the shell as partly exposed at 
the end of the body, and this agrees with the imperfect specimen 
brought home by Captain Belcher, and described by Mr. Owen. 
Mr. Cranch’s fragment, that described by M. De Blainville, and 
the nearly perfect specimens brought home by Mr. Earl, first 
figured by Mrs. Gray in the Annals , have the shell entirely enclosed, 
and the hinder part of the body furnished with a thick ring-like 
fleshy substance, pierced in the centre, and having a slight semicir- 
