310 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [100] 



size and high development of their organs of locomotion, especially of 

 the caudal fin and siphon, and for the presence of a broad, thin web 

 along the lower side of the lateral arms, outside the suckers. 



The tentacular arms are, like those of Arehiteuthis, very long, slender, 

 and provided at the base of the club with smooth-rimmed connective 

 suckers, alternating with rounded tubercles, for the mutual adhesion of 

 the two arms ; the central part of the club is, as in Arehiteuthis, pro- 

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

 smaller marginal ones on each side, of different form, alternating with 

 them. The lateral arms have a well-developed median crest (most de- 

 veloped 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 developed than 

 in typical Ommastrephes, in which a narrow marginal membrane occurs. 

 On the ventral arms the inner face is broader than on the others, and 

 the two rows of suckers are farther apart. The suckers on all the sessile 

 arms are strongly denticulated on the outer side of the rim, with smaller 

 or obsolete teeth on the inner side. 



Caudal fin very large, rhomboidal. Internal bone or pen similar to 

 that of Ommastrephes, decidedly hooded at the posterior end. 



Odontophore with seven rows of teetb ; median tooth with three large 

 denticles ; inner lateral teeth with two unequal points ; two outer Lat- 

 erals simple, slender. Eyes as in Ommastrephes. 



This group is related on one side to Arehiteuthis, on the other to Om- 

 mastrephes. The armature of the tentacular arms will distinguish it 

 from the latter, and the large caudal fin and broad membrane of the 

 sessile arms from former.* The dentition of the type is peculiar, so 

 far as known. In addition to the typical species, this genus will doubt- 

 less include several species with marginal webs that have hitherto been 

 referred to Ommastrephes, but they are often too indefinitely described 

 and figured to show the special characters referred to. 



Among those that belong, without much doubt, to this genus, in ad- 

 dition to those described below, are 8. Oualaniensis (Lesson), and S. pela- 

 gicus (Bosc), and possibly 0. gigas D'Orb., though the latter does not 

 have the wide lateral membrane on the arms. 



Sthenoteuthis megaptera Verrill. — (Large Broad-finned Squid.) 



Arehiteuthis megaptera Verrill, Amer. Journ. Sci., vol. xvi, p. 207, 1878. 



Tryon, Manual of Conchology, vol. i, p. 187 (description copied from preced- 

 ing paper). 

 Sthenoteuthis megaptera Verrill, Trans. Conn. Acad., vol. v, pp. 223, 286, pi. 21, 

 figs. 1-9, pi. 27, fig. 6, pi. 45, figs. 5, 5 a, 1880-'81 ; Amer. Journ. Sci., vol. 

 xix, p. 288, 1880. 



Plate XVI, figs. 1-10. 

 Although very much larger and stouter than any of the ordinary 

 squids, this species is much smaller than the species of Arehiteuthis, the 



* According to the statement of Gervais, Arehiteuthis dux has similar membranes. 



