344 A. E. Verrill — North American Cephalo2yods. 



without a keel ; those of the third pair are strongly compressed, bent 

 outward at base, and furnished with a higli median keel, starting 

 from the base, but highest in the middle ; ventral arms triangular at 

 base, with a wade membrane on the upper angle, wliich 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 broad, 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 chroraatophores, pretty uniformly and regularly scattered 

 everywhere on the body, on a pale ground-color ; when expanded the 

 chroraatophores 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 arras ; under side of caudal fin white. 



In alcohol, a medium-sized specimen measures, from tip of tail to 

 base of dorsal arms, 80"'" ; total length of mantle Tl'"'™ ; breadth 

 of body, 22""" ; breadth of caudal fin, 52"™ ; length of fin, 39"'" ; length 

 of dorsal arms, from base, 17""; of second pair, 23""; of 3d pair, 

 31"" ; of ventral arms, 31"'" ; of tentacular arms, 46"" ; of club, 22"°^. 



