CEPHALOPODA. 175 
some of the marlstone quarries of the central counties, and the 
las cliffs of Dorsetshire. It is also probable that they lived in 
a moderate depth of water, and preferred a muddy bottom to 
rocks or coral-reefs, with which they would be apt to come in 
perilous collision. Belemnites injured in the lifetime of the 
animal haye been frequently noticed. 
BELEMNITELLA, D’Orb. 
Synonym, Actinocamax, Miller (founded on a mistake.) 
Type, B. mucronata, Sby. Pl. Il., Fig. 6. 
Distribution, Europe; North America. 6 species. Upper 
greensand and chalk. 
The guard of the belemnitella has a straight fissure on the 
ventral side of its alveolar border ; its surface exhibits distinct 
vascular impressions. The phragmocone is never preserved, but 
casts of the alveolus show that it was chambered, that it had 
a single dorsal ridge, a ventral process passing into the fissure 
of the guard, and an apical nucleus. 
XIPHOTEUTHIS, Hux. (1864). 
Shell with a long phragmocone enyeloped in a calcareous 
sheath. 
Fossil. ispecies. Lias. England. 
ACANTHOTEUTHIS (Wagner), Minster. 
Etymology, acantha, a spine, and teuthis. 
Synonyms, Kaleeno (Minster). Belemnoteuthis ? 
Type, A. prisca, Ruppell. 
Founded on the fossil hooks of a calamary, preserved in the 
Oxford clay of Solenhofen. These show that the animal had 
ten nearly equal arms, all furnished with a double series of 
horny claws, throughout their length. <A pen like that of the 
ommastrephes has been hypothetically ascribed to these arms, 
which may, however, have belonged to the belemnite or the 
belemnoteuthis. 
Fossil. 17 species. Oolite. 
BELEMNOTEUTHIS (Miller, Pearce, 1842). 
Type, B. antiquus (Cunnington), Fig. 40. 
Shell consisting of a phragmocone, like that of the belemnite; 
a horny dorsal pen with obscure lateral bands; and a thin 
fibrous guard, with two diverging ridges on the dorsal side. 
