LITUIDJE. 
113 
Suborder III. Belemnophora. 
Shell calcareous, internal, chambered ; chamber traversed bj a 
siphon. 
Cephal. Polarnaxia Spirularia Rajin. Anal. Nat. 141. 1815. 
Cephal. Spiriformia and Belemnomorpha Broun , Gesch. der Nat a iii. 
536. 
Fam. YII. LITUIDiE. 
Body subcylindrical, oblong, end rounded ; sometimes furnished 
with a thickened belt, and with a small semilunate fleshy fin on 
each side. Mantle free all round, cartilage on the inner side 
of the ventral surface linear. 
Eyes covered with the skin, with a lower eyelid. Buccal mem- 
brane without cups. 
Arms. Sessile arms triangular, tapering; cups numerous, equi- 
distant, very small, slightly pediceled in six longitudinal series. 
Tentacular arms elongate, peduncled, cylindrical ; club ? 
Siphuncle conical, with an apical valve. 
Shell internal, shelly, spiral, placed symmetrically at the hinder 
part of the body, the last chamber being in the central line of 
the back ; chambered, the chambers furnished with a siphon, the 
last chamber only large enough to contain a very small part of 
the animal. 
Spirulidse Owen , Trans. Zool. Soc. ii. 1836; D'Orh. Moll. Viv. et 
Fos. i. 160. 306. 1845. 
Lituidse Gray , Proc . Zool. Soc. 1847, 206. 
Spirularia (pars) Rajin. Anal. Nat. 141. 1815. 
Sepiacea (pars) Desk. Ency. Meth. iii. 
Sepiadae (pars) Geinitz , Grund der Verst. 261. 1845. 
Spiriformia Broun , Gesch. de Nat. iii. 535. 
1. Lituus. 
Synopsis of Genera. 
A. Shell thin , apex not coated . 
