MUSEUM OF COMPARATIVE ZOOLOGY. 103 



the hectocotylized arm of some Octopods as to suggest the possibility of a 

 similar xxse, for sexual purposes. The suckers are crowded in 4 indistinct 

 rows. Their pedicels are long and slender, having beyond the middle a large 

 dark purple, fluted, swollen portion, beyond which the pedicel is more slender; 

 the cup of the suckers is small and lateral, with a very oblique, homy rim, 

 which is not denticulated. 



Heteroteuthis tenera Verrill. 



Amer. Jour. Sci., XX. p. 392, November, 1880 ; Proc. Nat. Mus., III. p. 360, 1880 ; 

 Traus. Comi. Acad., V., PI. XLVI. figs. 2-2rf, 3-3 6, 1881. 



Plate III. Figs. 5, r.b. Plate VII. Figs. 2 - 2d, 3 _ 3b. 



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

 when lixing. 



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 with a dorsal angle extending 

 somewhat forward over the neck. Fins very large, thin, longer than broad, 

 the outer edge broadly rounded, the anterior edge extending forward quite as 

 far as the edge of the mantle, and considerably beyond 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 eyelid slightly 

 thickened. Arms rather small, unequal, the dorsal ones considerably shorter 

 and smaller than the others. In the male the left dorsal arm is greatly modi- 

 fied, and very diff"erent from its mate. Lateral and ventral arms 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 becom- 

 ing 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 around the middle, and a very small round aper- 

 ture, furnished with a smooth rim. In the female the corresponding suckers 

 are about twice as broad as the rest, on the lateral arms. The suckers are in 

 two regular rows, on the lateral and ventral arms in both sexes. In the male, 

 the left dorsal arm becomes thickened, and larger from front to back, and 

 is usually curled backward ; its suckers become smaller and much more numer- 

 ous 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 equalling that of the suckers. The right 

 arm remains normal, with two alternating rows of suckers, regularly decreasing 

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

 slender, extensible ; club distinctly enlarged, usually curled in preserved exam- 



