SYSTEMATIC 
CO ECO Oe a. . 

Crass CEPHALOPODA. 
Head large, connected with the body by a neck, and furnished 
with complex, sessile or pedunculated eyes; mouth with a pair 
of mandibles or beaks, resembling those of a parrot, edged with 
fleshy lips, and surrounded by a circle of arms. 
As pointed out in the structural portion of this work, the 
Cephalopoda are related to the vertebrata in several particulars: 
in the mode of segmentation of the vitellus, in their internal carti- 
laginous support—a simplified skeleton ; in their circulation fur- 
nished with true capillaries, their blood corpuscles, their more 
highly developed eyes, mandibles, etc. 
Differing from other mollusks by their symmetry as well as in 
the above details, they nevertheless present, with more or less 
modification, the main distinctive features common to other 
classes of the subkingdom Mollusca. 
The Cephalopoda are essentially carnivorous ; their nourish- 
ment is derived from fish, the migrations of which they follow, 
and from pteropod mollusca.. Certain sedentary species eat 
crustaceans, nudibranchiate and bivalve mollusks and bryozoa. 
After their exclusion, the young prey upon polyps, notably on 
those of the family Gorgonidx, so common on the Algerine 
coast, and some of which, perhaps, furnish the material necessary 
for the growth or solidification of the cuttle-bone. A little larger, 
they attack with avidity those elegant chaplets of pearls, the 
rainbow-hued eggs of Holis and Doris. 
The number of cephalopods of small size is exceedingly great, 
but they become the prey of a multitude of enemies. On the 
10th Jan., 1858, the Dutch ship Vriendentrouw sailed for two 
hours through dead Loligos, covering the surface of the sea as 
far as the eye of the lookout could reach. Mr. Vrolik found in 
the stomach of a Hyperoodon about ten thousand mandibles of 
Loligo. 
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