A. E. Yerrtll — Isforth American Cephalopods. 303 



middle and directly united to the head, so as to leave no free edge 

 medially, by a rather wide commissui-al band, the sides of which 

 diverge as they extend backward within the mantle. Caudal fin 

 long, narrow, lanceolate, narrowly acuminate to a very long, acute 

 tip ; the anterior insertions 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 lai-ge 

 and prominent, extending forward between the eyes, but without a 

 special groove ; dorsal surface firmly united to the head by a thick 

 commissure, leaving about half the length free ; oj^ening large, 

 without any valve. 



Arms comparatively small and short, none of them conijilete, in 

 our specimen, except those of the 3d and 4th pairs, which are nearly 

 equal in length, the ventral ones a little the shortest and most slen- 

 der ; the dorsal and 2d 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 2d pair with the 3d 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 different 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 suckers are ventricose and 

 urceolate, like those of the ventral arms, but along the middle por- 

 tion 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 eight bridles, or commissures, of which the upper one is 

 double. Exposed part of the beak black ; mandibles very acute, 

 strongly incurved. 



Pen very thin and narrow, and of nearly uniform width (4""") for 

 more than half its length ; at about four-sevenths of its length, from 



