8 AMERICAN MARINE CONCHOLOGY. 
capture by varying its tints according to the nature of the ground 
over which it passes, and eludes its enemies, when pursued, by 
discoloring the water around it with the contents of its ink-bag. 
Synopsis of Genera. 
Arms with two rows of cups. Body round, without fins. OcToPUs. 
Arms with one row of cups, bearded and united by a broad web. Body 
finned. CIRRHOTEUTHIS. 
Genus OCTOPUS, Cuvier. 
Regne Animal, ii. 1817. 
1. O. RUGosUS, Bose. Fig. 1. 
Act. de la Soc. d’Hist. Nat., t. 15, f. 1, 2. 1792. 
Sepia granulosa, Bosc. Buff., Vers. i. 47. 1802. 
Sepia granulatus, Lamarck, Mem. Soc. Hist. Nat., i. p. 2. 1799. 
Octopus Barkeri, Ferussac, Orb. Sal. Céph. 54, No. 3. 1826. 
Octopus Americanus, Blainville, Dict. Sc. Nat. xlili. 185. 1826. 
Body oval, purse-shaped, large, with a deep groove above. Head, 
arms, and upper part of the body covered with roundish tuber- 
cles. Head short, warty; ocular beard, one, elongated. Arms 
short, thick, conical, their proportional lengths 4, 3, 2,1. Cups 
large, of upper part of arm rather smaller, lowest one-rowed. Web 
short. When alive, violet-brown, white beneath ; side of the arms 
netted with brown lines. 
North Carolina to South America ; also Indian Ocean. ? 
Genus CIRRHOTEUTHIS, Eschricht. 
Noy. Act. Nat. Cur., xviii. 625. 1836-8. 
1. C. Muuuerti, Eschricht. Fig. 2. 
Nov. Act. Nat. Cur., xviii. 1836-8. | 4 
Body smooth, oblong, three-lobed. Fins longer than broad, 
blunt, depressed. Eyes very small. Arms equal, quadrangular. 
Cups very small, oval, about thirty; beards between the cups fili- 
form. 
Arctic America. 
OrpvER DECAPODA. 
* Shell internal, solid, horny. 
Family Lorticopsip%. Eyes naked. Mantle supported by two 
internal fleshy bands. Siphuncle simple. Fins semicircular. 
Family OnycnorruTHip®. Eyes naked, with a sinus above. 
