[175] CEPHA.LOPODS OF NORTHEASTERN COAST OF AMERICA. 385 



Heteroteuthis tenera Verrill. 



Aroer. Journ. Sci., xx, p. 392, November, 1880 ; Proc. Nat. Mus., iii, p. 360, 1880 ; 

 Bulletin Mus. Comp. Zool.,xiii, p. 103, pi. 3, figs 5-5&; pi. 7, figs. 2-2d, 3-36. 

 1881 ; Trans. Conn. Acad.,v, p. 357, pi. 46, figs. 2-2(7, 3-36 ; pi. 47, figs. 5-56, 1881. 



Plate XXXIII. Plate XXXIV, figure 1. 



A small and delicate . species, very soft, translucent, and delicately 

 colored when living. 



Body short, cylindrical, scarcely twice as long as broad, posteriorly 

 usually round, but in strongly contracted, preserved specimens, often 

 narrowed and even obtusely pointed; front edge of mantle sometimes 

 with a dorsal angle extending somewhat forward over the neck, but 

 usually emarginate in alcoholic specimens. Fins very large, thin, longer 

 than broad, the outer edge broadly rounded, the anterior edge extend- 

 ing forward quite as far as the edge of the mantle, and considerably be- 

 yond the insertion of the fin, which is itself well forward. The length 

 of the fin is about two-thirds that of the body ; the base or insertion of 

 the fin equals about one-half the body-length ; the breadth of the fin is 

 greater than one half the breadth of the body. Head large, rounded, 

 with large and prominent eyes ; lower eyelids free, slightly thickened; 

 pupils indented above. Arms rather small, unequal, the dorsal ones con- 

 siderably shorter and smaller than the others, the second pair longest. 



In the male, the left dorsal arm is greatly modified, and very different 

 from its mate; lateral and ventral arms are subequal. In both sexes, and 

 even in the young, the suckers along the middle of the four lateral and 

 two ventral arms are distinctly larger than the rest, but in the larger 

 males this disparity becomes very remarkable, the middle suckers (Plate 

 XXXIII, figs. 1, la, lb, 3) becoming greatly enlarged and swollen, so 

 that eight to ten of the largest are often six or eight times as broad as 

 the proximal and distal ones ; they are deep, laterally attached, with a 

 raised band round the middle, and a very small round aperture, fur- 

 nished with a smooth rim. In the female (Plate XXXIV, fig. 1) the cor- 

 responding suckers, on the lateral arms, are about twice as broad as the 

 rest. The suckers are in two regular rows, on the lateral and ventral 

 arms, in both sexes, except at the tip, where they form four rows. 



In the male, the left dorsal arm becomes thickened, and larger from 

 front to back, and is usually curled backward (Plate XXXIII, figs. 1-3); 

 its suckers become smaller and much more numerous than on the right 

 arm, being arranged in four crowded rows, except near the base, where 

 there are but two; the sucker-stalks also become stout and cylindrical, 

 or tapered, their diameter equaling that of the suckers. The right arm 

 remains normal, with two alternating rows of suckers, regularly de- 

 creasing to the tip, as in both the dorsal arms of the female. 



Tentacular arms long, slender, extensible ; club distinctly enlarged, 

 usually curled in preserved examples. The suckers on the club are nu- 

 merous, unequal, arranged in ab jut eight close rows; those forming the 

 two or three rows next the upper margin are much larger than the rest, 

 S. Miss. 59 25 



