24 NEW-YORK FAUNA — MOLLUSCA. 
ORDER I. CEPHALOPODA. 
Animal enclosed in a muscular tunic open in front, from which arises a distinct head. In 
many species, this tunic is enlarged on each side into fleshy fins. Mouth terminal, armed 
with two horny mandibles, and the tongue with horny points. Eyes generally large, 
sessile. Head surrounded with numerous long fleshy arms or feet, serving for locomotion 
or prehension. 
Ons. The animals of this order are exceedingly varied in their form, but all are united by 
the common character of feet or arms surrounding the head, which gives the name to the 
order. The sexes are separate. The shell either entirely external, or partially so; or wholly 
internal, rudimentary ; univalve, of one or many chambers, and much varied in its form; 
the chambers connected. All marine. Many fossil genera. 
FAMILY SEPIAD. 
Animal sack-shaped, with or without fleshy fins.. Head large, distinct, surrounded by eight 
or ten unequal arms with rows of suckers on their internal surface, and occasionally with 
hooks. Shell, when not external, represented by a solid cretaceous or horny and flexible 
substance within the body. 
Oss. This family, originally equivalent to the old genus Sepia of Linneus, now comprises 
more than thirty species, arranged under eleven genera. It corresponds with the Cephalopo- 
des sepiaires of Lamarck, and the order Cryptodibranches of Blainville. The animals com- 
prising this family have been celebrated from the earliest times for their singular property of 
surrounding themselves with an inky fluid, with which they envelope themselves to evade 
pursuit. They are carnivorous, destroying many fish and crabs. The coloring substance 
named sepia, is obtained from these animals. In this country, their only use is as bait in the 
cod fishery. 
GENUS LOLIGO. Lamarck. 
Animal enclosed in an elongated cylindrical sac, enlarged into fleshy fins, and pointed beneath. 
Dorsal edge of the sac very distinct from the head, and sometimes elongated into a point. 
The eight sessile subequal arms furnished with suckers along their whole length; the two 
long arms with suckers on their enlarged extremities. Suckers occasionally furnished with 
hooks. The rudiment of a shell represented by a thin horny flexible blade, varying in 
form, but usually enlarged, and resembling a feather. This internal support, the horny 
jaws, and the ink-bags of various species, have been found fossil. 
