222 



A. E. Verrill — North American Gephalopods. 



of the suckers, some of them (<?, g) slightly exceeding the largest of 

 those described on p. 201, but showing no distinct variation; others 

 (A) are completely intermediate between the two principal forms, 

 having very oblique rims, with a small aperture, but distinctly 

 denticulate all around, the denticles on the inner margin being 

 distinctly smaller than on the outer. 



The following table of measurements will supplemeut those on 

 page 201. 



Measurements of sucker-rims from short arms (milliineters). 



Diameter, at base, 



Diameter of aperture. 



Height or breadth of ring, at back, 



" " ■' front side, 



Nnmber of distinct denticles, . 



Sthenoteuthis, gen. nov. 



(Type Arcliiteuthis megaptera Verrill.) 



This group is instituted to include certain species of squids, remark- 

 able for the large size and high development of their organs of loco- 

 motion, especially of the caudal fin and siphon, and for the presence 

 of a broad, thin web along the lowej- side of the lateral arms, outside 

 the suckers. 



The tentacular-arms are, like those of Architeuthis, very long, 

 slender, and jarovided, at the base of the club, with smooth-rimmed 

 suckers alternating with rounded tubercles, for the mutual adhesion 

 of the two arms; the central part of the club is, as in Architeuthis, 

 provided with two central rows of large serrated suckers, and a row 

 of smaller marginal ones, on each side, of diiferent form, alternating 

 with them. The lateral arms have a well-developed median crest, 

 (most developed on the third pair) along the outer side ; on the lower 

 inner angle there is a thin, membranous web, often more than twice 

 as wide as the arm, along the whole length, much more highly de- 

 veloped than in typical Oiumastrephes, in which a narrow marginal 

 membrane occurs. On the ventral arms the inner face is broader than 

 on the others, and the tw^o rows of suckers are wider apart. The 

 suckers on all the sessile arras are strongly denticulated on the outer 

 side of the rim, with smaller or obsolete teeth on the inner side. 



Caudal fin very large, i-homboidal. Internal bone or pen similar 

 to that of Ommcistrephes. 



Odontophoi-e with seven rows of teeth, median tooth with three 



