CEPHALOrODA 163 



the rest is free and coiled up. It lias no enlargement like that 

 of the Tremoctopus (PL I., Fig. 3); the filiform appendage 

 proceeds from the smaller extremity, and sometimes remains 

 entangled in the coloured cyst near the base of the outer side 

 of the Hectocotylus. It has a chain of nervous ganglia in its 

 axis. 



It was the nautilus {'primus) of Aristotle, who described it as 

 floating on the surface of the sea, in fine weather, and holding 

 out its sail-shaped arms to the breeze. It does not use its arms 

 as sails, but it sometimes uses them as oars when it wishes to 

 progress slowly, while floating on the surface of the sea. 



Distribution : 4 species of argonaut are known ; they inhabit 

 the open sea throughout the warmer parts of the world, and 

 are most active during the night. Captain King took several 

 from the stomach of a dolphin caught upwards of 600 leagues 

 from land. 



Fossil, 2 species. Tertiary. A. Mans is found in the sub- 

 apennine tertiaries of Piedmont. This species is still living in 

 the Chinese seas, but not in the Mediterranean. 



Family II. — Octopodid^. 



Arms similar, elongated, united at the base by a web. Shell 

 represented by two short styles, encysted in the substance of 

 the mantle. (Owen.) 



Octopus, Cuvier. Poulpe. 



Etymology, odo, eight, pous {poda), feet. 



Synonyms, cist opus. (Gray.) 



Example, 0. tuberculatus, BL, PI. I., Figs. 1 and 2 (man 

 dibles). 



Body oval, warty or cirrose, without fins ; arms long, un- 

 equal ; suckers in two rows ; mantle supported in front by the 

 branchial septum. 



The octopods are the "polypi" of Homer and Aristotle; 

 they are solitary animals, frequenting rocky shores, and are 

 very active and voracious ; the females oviposit on sea-weeds, 

 or in the cavities of empty shells. In the markets of Smyrna 

 and Naples, and the bazaars of India, they are regularly ex- 

 posed for sale. " Although common (at St. Jago) in the pools 

 of water left by the retiring tide, they are not very easily caught. 

 By means of their long arms and suckers they can drag their 

 bodies into very narrow crevices, and when thus fixed it re- 



