CEPHALOPODA. 201 
HAMITES, Parkinson. 
Boy, hamus, a hook. 
Example, H. attenuatus (Pl. IIT., Fig. 15). 
Shell hook-shaped, or bent upon itself more than once, the 
courses separate. 
Distribution, 58 species. Neocomian—Chalk. South America 
(Tierra del Fuego), Europe, India. 
a 
Fig. 65, Sutures of Hamites cylindraceus, Defr.* 
The inner courses of this shell probably break away, or are 
**decollated,” in the progress of its growth. (Iforbes.) M. 
D’Orbigny has proposed a new genus, hamulina, for the twenty 
neocomian species. 
PrycHocERAs, D’Orbigny. 
Etymology, ptyche, a fold. 
Example, P. emericianum, D’Orbigny (PI. IIL., Fig. 14). 
Shell bent once upon itself; the two straight portions in 
contact. 
Distribution, 8 species. Neocomian—Chalk. Britain, France, 
India. 
BAcuLITES, Lamarck. 
Etymology, baculus, a staff. 
Example, B. anceps (Pl. III., Fig. 13). 
Shell straight, elongated; aperture guarded by a dorsal process. 
Distribution, 17 species. Neocomian—Chalk. Europe, South 
America (Chili), India. 
Baculina, D’Orbigny, 2 species. B. Rouyana. Neocomian. 
France. Sutures not foliated. 
The chalk of Normandy has received the name of. baculite lime- 
stone, from the abundance of this fossil. 
* Fig. 65. Space between two consecutive sutures of the right side, from a specimen 
in the British Museum. a, dorsul line; 6, ventral. Baculite limestone, Fresville. 
K 3 
* 
