8 AMERICAN MARINE CONCHOLOGY, 



capture by vaiying 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. 



Sy7ioj)sis of Genera. 

 Arms with two rows of cups. Bod^' round, without fins. Octopus. 



Arms with one row of cups, bearded and united by a broad web. Body 

 finned. Cirrhoteuthis. 



Genus OCTOPUS, Cuvier. 

 Regue Animal, ii. 1817. 



1. 0. RUGOsus, Bosc. Fig. 1. 



Act. de la Soc. d'Hist. Nat,, t. 15, f. 1, 2. 1792. 



Sepia granulosa, Bosc. Bufl"., Vers. i. 47. 1803. 

 Sepia granulatua, Lamarck, Mem. Soc. Hist. Nat., 1. p. 2. 1799. 

 Octopux Barken, Ferussac, Orb. Sal. Ceph. 54, No. 3. 1826. 

 Octopus Americanus, Blainville, Diet. Sc. Nat. xliii. 185. 1826. 



Body oval, purse-shaped, lai'ge, with a deep groove above. Head, 

 arms, and upper part of the body covered with roundish tuber- 

 cles. Head short, wart}^ ; 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. AVeb 

 short. When alive, violet-brown, white beneath ; side of the arms 

 netted with brown lines. 



North Carolina to South America ; also Indian Ocean. ? 



Genus CIRKHOTETJTHIS, Eschricht. 

 Nov. Act. Nat. Cur., xviii. 635. 1836-8. 



1. C. MuLLERi, Eschricht. Fig. 2. 



Nov. Act. Nat. Cur., xviii. 1836-8. 

 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. 



Order DECAPODA. 



* Shell internal, solid, horny. 



Family Loligopsid^. Byes naked. Mantle supported b}-^ two 

 internal fleshy bands. Siphuncle simple. Fins semicircular. 

 Family Onychoteuthid^. Ej^es naked, with a sinus above. 



OSI 



