[ 127 ] CEPHALOPODS OF NORTHEASTERN COAST OF AMERICA. 
long, slender, acute tail; mantle soft and flabby, with a capacious bran¬ 
chial cavity; anterior dorsal edge advancing somewhat in the middle 
and directly united to the head, so as to leave no free edge medially, by 
a rather wide commissural band, the sides of which diverge as they 
extend backward within the mantle. Caudal fin long, narrow, lanceo¬ 
late, narrowly acuminate to a very long, acute tip ; the anterior inser¬ 
tions are wide apart, and the anterior border is rounded. Head short 
and small, exclusive of the eyes, which are very large, globular, and 
prominent, their lower sides in contact beneath the head; openings 
round, looking somewhat downward; pupils large and round; lids thin 
and simple. Siphon very large and prominent, extending forward be¬ 
tween the eyes, but without a special groove; dorsal surface firmly 
united to the head by a thick commissure, leaving about half the length 
free; opening large, without any valve. 
Arms comparatively small and short, none of them complete in our 
specimen except those of the third and fourth pairs, which are nearly 
equal in length, the ventral ones a little the shortest and most slender; 
the dorsal and second pairs of arms have lost their distal portions, but 
the parts of the dorsal arms remaining correspond in size with the 
ventral ones, and those of the second pair with the third pair. The 
arms are all united together by a thin, delicate basal web, which extends 
up some distance between the arms (farthest between the dorsal pair), 
and then runs along the sides of the arms, as broad, thin marginal 
membranes, to the tips. Suckers of the ventral arms smaller and dif¬ 
ferent in form from those of the others, all of them being urceolate, with 
narrow apertures, surrounded by a slightly enlarged border, and having 
small horny rings, with the edge entire, or nearly so, on the proximal 
suckers, but on the smaller ones, toward the tip, with a few broad, blunt 
teeth on the outer edge. On the dorsal and lateral arms the basal suck¬ 
ers are ventricose and urceolate, like those of the ventral arms, but along 
the middle portion of these arms the suckers become much larger, and 
have a broad, shallow form, with wide apertures and expanded bases; the 
horny rings of these larger suckers are divided into several broad, bluntly 
rounded teeth on the outer edge; toward the tips of the arms the smaller 
suckers again become deeper, with more contracted apertures, and with 
a few more prominent denticles on the rings. 
Outer' buccal membrane with seven obtuse angles, and united to the 
arms by seven bridles, or commissures, of which the upper one is double. 
Exposed part of the beak black; mandibles very acute, strongly in¬ 
curved. 
Pen very thin and narrow, and of nearly uniform width (4 mm ) for more 
than half its length; at about four-sevenths of its length from the 
anterior end it gradually expands laterally into a broad, very thin, lan¬ 
ceolate form, becoming, opposite the broadest part of the fin, 30 mm wide, 
with very delicate lateral expansions and with a pretty strong dorsal 
keel; farther back it tapers and is very acuminate, the lateral margins 
