344 A. E. Verrill — North American Cephalopoda. 
without a keel; those of the third pair are strongly compressed, bent 
outward at base, and furnished with a high median keel, starting 
from the base, but highest in the middle; ventral anus triangular at 
base, with a wide membrane on the upper angle, which expands at 
the base, and connects them with the third pair; a narrower mem- 
brane runs along the ventral margins. Tentacular arms rather stout 
at base ; compressed farther out, in extension about as long as the 
body ; club well-developed, about twice as broad as the rest of the 
arm ; its dorsal keel is thin, elevated, oblique, commencing at about the 
middle of the club and extending to the tip. The larger tentacular 
suckers are very regularly arranged in four rows, of 8 to 10 each, the 
lateral ones being not very much smaller than the median ones. 
The distal part of the club is covered with four regular rows of small 
suckers, and there is a terminal group of smaller, smooth-rimmed 
ones. The larger median suckers are broad cup-shaped, rather 
larger than the largest suckers of the lateral arms ; their horny rims 
are armed with regular, sharp, incurved teeth, smaller on the inner 
side of the sucker, but there are few or no small teeth alternating 
-with the larger ones. The lateral suckers are relatively large, deep 
cup-shaped, oblique, with very sharp incurved teeth on the outer 
margin. The membranous borders of the large suckers are covered 
with minute, sharp, chitinous scales. 
The suckers of the short arms are very deep and oblique, cup- 
shaped ; their rims are much the highest on the outer and distal side, 
where the edge is divided into several bx*oad, bluntly rounded denti- 
cles, separated by narrow intervals. 
The pen is short, with a broad-lanceolate blade ; the narrow part 
of the shaft is short; a thin border, widening backward to the blade, 
commences about half way between the tip and the proper blade ; the 
latter is broad and thin, marked with divergent lines ; posterior end 
obtuse. 
The color is peculiar. It consists, in alcoholic specimens, of dark 
purplish cliromatophores, pretty uniformly and regularly scattered 
everywhere on the body, on a pale ground-color ; when expanded the 
chromatophores are large and rounded; above the eyes they are so 
closely crowded as to form dark blotches ; they also cover the outer 
surfaces of all the arms ; under side of caudal fin wdiite. 
In alcohol, a medium-sized specimen measures, from tip of tail to 
base of dorsal arms, 80 mm ; total length of mantle 7l mm ; breadth 
of body, 22 ram ; breadth of caudal fin, 52 mm ; length of fin, 39 mm ; length 
of dorsal arms, from base, I7 ram ; of second pair, 23 mm ; of 3d pair, 
3 l mm ; of ventral arms, 31 mm ; of tentacular arms, 46 ram ; of club, 22 mm . 
