CEPHALOPODS 



469 



GENUS Argonauta 



A. arffo. In this species, the paper-nautilus, the shell, which is pos- 

 sessed only by the female, is not chambered. The animal rests in the 

 shell, but has no or- 

 ganic connection 

 with it other than by 

 the membranous ex- 

 pansions at the ex- 

 tremities of the two 

 dorsal arms, which 

 secrete it and hold it 

 in place. The pur- 

 pose of the shell is 

 to hold and protect 

 the eggs. 



GENUS Loligo 



Argonauta argo, side view of shell. 



L. Pealei. In this 

 species the body is 

 cylindrical, tapers to a point, and has a flat appendage in front. The 

 fins are terminal, half, or more than half, as long as the body, united in 

 a point posteriorly, and obtusely rounded on the outer angles. The 

 head is a little narrower than the mantle. There are eight sessile, sub- 

 triangular arms furnished with two series of 

 suckers which are hemispherical and stalked, and 

 two long retractile tentacular arms dilated at the 

 extremities, bearing four rows of suckers. It has 

 a pen- or quill-shaped cartilaginous substance in 

 the dorsal integument of the mantle. Common 

 from Cape Cod to South Carolina. 



L. brevis. A small short -bodied species, with 

 short rounded caudal fins. It is common from 

 South Carolina to Florida, and extends as far north 

 as Delaware Bay. 



GENUS Ommastrephes 



O. illecebrosus. A species similar to L. Pealei, 

 but with shorter fins. These are broad and pear- 

 shaped, one third wider than they are long, and 

 usually reach less than one half the length of the 

 mantle. They are straight on the posterior end, 

 and form nearly a right angle, while the upper 

 margins are rounded. The head is as broad as the 

 mantle. The arms are stout and taper to an acute 

 point. The tentacular arms are long when ex- 

 panded. The species is abundant from Cape Cod 

 to Newfoundland, and is found as far south as 

 toiigo Pealei, ycmng fa. Newport, Rhode Island. This is the squid which is 

 male ; dorai view. used so extensively iii the Banks fishery as bait. It 



