A. E. Verrill — North American Cephalopoda. 271 
along the outer angle, which is acute, while the ventral angle is 
rounded. 
The tentacular-arms (Plate XXVIII, figs, la, 2) are long; when 
extended, in fresh specimens, they reach hack beyond the base of the 
caudal fin. They are rather stout, rounded-trapezoidal along the 
peduncular portion ; along the upper-outer angle a thin fold runs 
from the base to the tip, becoming a wide carina on the backside of 
the club ; two less marked folds run along the inner angles, defining 
a narrow inner face, along the whole length, but on this face thex - e 
are no suckers, except close to where it begins to expand into the 
broader face of the club; along the sides of the club, the marginal 
membranes become much wider, rising to a level with the suckers. 
In the male of our species, one of the ventral arms (Plate XXVIII, 
figs. 3, 3a) is strongly hectocotylized, somewhat as in Eoligo. But 
in this species it is the right arm, about as often as the left, that is 
modified. Toward the tip of the arm, for some distance, the pedicels 
of the suckers, especially of the outer row, become shorter, and the 
bases of the •sucker-stalks become larger, broader, and transvei’sely 
compressed, while the cxxps of the suckers thexnselves decrease rapidly, 
till they become very minxxte, and oxi a mxmber of the xxxost flattened 
and largest stalks, they are entirely abortive, in the case of the 
medium sized males, bxxt, very close to the tip, they may again become 
normal. The inner row of suckers is more or less modified, in a 
similar manner; bxxt fewer of the sxxcker stalks are affected, and these 
are, xxsually, not so extensively altered, though in the larger males 
xxiaxxy of them are commonly destitute of cxxps and have the same flat- 
tened form as those of the outer row, with which they are usxxally 
xmited along the median line of the arm, forxning a zigzag ridge. 
In a very large xxiale (J), with the right ventral anxx modified, the 
altei'ation of the sxxckei’-stalks becomes obvioxxs at aboxxt the 45th 
sxxcker, and there are, beyond this, about 80 modified suckers, ex- 
tending to the very tip ; of these aboxxt 30, in the outer row, are 
represented only by the flat, lamelliform bases of the sucker-stalks, 
without cups; on the inner row, the small cups extend for aboxxt ten 
suckers farther than on the oxxter. The lamelliform processes are united 
medially in a zigzag line, along the entire tip. The modified part is 
about an inch in length. This arm is as long as its mate, (though in 
other specimens it is often shorter) ; but it is broader, stouter, and 
more blunt at tip, both the inner face and lateral membrane being in- 
creased in width. The younger males, 4 to 0 in. long, have the corre- 
sponding suckers less extensively modified, and the cups, though very 
much reduced in size, arc usually present on all or nearly all the stalks. 
