MUSEUM OF COMPARATIVE ZOOLOGY. 103 
the hectocotylized arm of some Octopods as to suggest the possibility of a 
similar use, 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 eup of the suckers is small and lateral, with a very oblique, horny rim, 
which is not denticulated. 
Heteroteuthis tenera VERRILL. 
Amer. Jour. Sci., XX. p. 392, November, 1880 ; Proc. Nat. Mus., III. p. 360, 1880 ; 
Trans. Conn. Acad., V., Pl. XLVI. figs. 2-2d, 3—3 b, 1881. 
Plate XII. Figs. 5,5». Plate VII. Figs. 2-24, 3- 35. 
A. small and delicate species, very soft, translucent, and delicately colored 
when living. 
Body short, cylindrieal, 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 different from its mate. Lateral and ventral arms subequal. 
Tn both sexes, and even in the young, the suckers along the middle of the four 
lateral and two ventral arms are distinetly 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 erowded 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 distinetly enlarged, usually curled in preserved exam- 
