114 CATALOGUE OF CEPHALOPODA. 



B. Shell apex enveloped in a thickened lamina?- Coat, more or less 



produced behind. 



2. Spirulirostra. Apex of shell spinal. 



3. Beloptera. Apex of shell nearly straight. 



Minister has given a genus under the name of Cornicidina, tvpe 



C. Ehrenbergi 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. — Recent. 



1. LITUUS. 



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. 



Peron 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- 



