*4. E. Yerrill — North American Cephalopoda. 
391 
Plate XLV, fig. 1-2 cl. Plate XLIX. fig. 1-1/ Plate LY, fig. 1-1 cl. 
Body elongated, tapering to an acute posterior end ; anterior edge 
of mantle nearly even dorsally, with a slight median emargination ; lat- 
eral angles well-marked, in line with the internal connective carti- 
lage, which forms a long, simple, longitudinal ridge. Caudal fin 
broad spear-shaped, broadest in advance of the middle ; the lateral 
angles are well rounded; the tip is very acute; the anterior lobes are 
broadly rounded, projecting forward beyond the insertion. Head 
large, short aud broad ; eyes large, occupying most of the sides of 
the head; eye-lids well developed, thickened, with a narrow, oblique 
sinus. Siphon large, in a deep groove, with two stout, dorsal bri- 
dles; lateral connective cartilages large, long-ovate, posterior end 
broadest. One olfactory crest on each side, behind the eye, in 
the form of a low, longitudinal membrane; slight indications of 
another, lower down ; a small, fleshy, flattened, projecting papilla 
near the auditory opening. The outer buccal membrane has seven 
distinct angles. Arms rather long and strong ; trapezoidal in sec- 
tion. The dorsal arms are considerably shorter tliau the others ; 
order of length is 1, 2, 4, 3 ; the 3d is but little longer than the 
second pair; ventral arms decidedly more slender than the others. 
Ventral arms with four rows of denticulated suckers, those of the two 
inner rows larger; lateral and dorsal arms with two marginal rows of 
small suckers and two inner rows of larger incurved hooks, enclosed, 
except at the sharp tips, in muscular sheaths, which have lateral basal 
expansions and short pedicels (PI. LY, fig. 1 b). Tentacular arms* long 
and strong, quadrangular ; in my specimen they reach back beyond 
the base of the fin ; the club is large and broad, with a long, 
narrow distal portion, having a strong dorsal keel; in the middle are 
two very large, curved hooks (fig. 1, It?), the distal one smaller; 
proximal to these there is a row of five smaller hooks, decreasing 
proximally, and between these and the large hooks there is, on 
one arm, a single small sucker ; on the other arm a single sucker 
takes the place of the proximal hook, while an odd, small sucker 
stands to one side of the row; along the upper margin of the club 
there is a broad band of small, denticulated suckers, on long ped- 
icels, arranged in oblique, transverse rows of five or six ; this band 
of suckers is interrupted opposite the large hooks; beyond the hooks 
♦The figure given (pi. XLIX, fig. 1,) of the somewhat injured tentacular club of 
the type of Cheloieuthia rapax, represents the structure nearly correctly, but ninny of 
the small suckers and tubercles on the arm. below the club, had been destroyed, the 
edge above e' is injured, and of the large hooks (a, a') only the sheaths remain. 
