232 A. E. Verrili— North American Cephalopods. 
the interval between the dorsal arms; the six others are opposite the 
three other pairs of sessile arms. The inner surface of this membrane 
is covered, near the periphery, with small rounded papille; externally 
it is connected to the arm by seven membranous bridles, correspond- 
ing to the seven angles; of these the dorsal one forks, one branch going 
to the inner margin of each dorsal arm; the upper lateral ones join 
the marginal membrane of the upper angle of the upper lateral arms; 
the lower lateral ones join the lower marginal membrane of the third 
pair of arms; the ventral ones join the marginal membrane outside of 
the sucker-bearing face of the ventral arms. In front of the bases of 
each of the dorsal and tentacular arms there is a large opening to the 
space beneath this membrane. 
The beak is closely surrounded by a thick, prominent, lobed and 
wrinkled, fleshy collar, with papillz on its inner surface; outside of 
this there is a smooth, sharp-edged, erect collar, less prominent than 
the inner one. 
The odontophore is similar to that of Ommastrephes ; it is sharply 
bent upon itself anteriorly, with the ventral end less than half as long 
as the dorsal; the dentigerous zone is yellowish brown in color and 
bordered laterally by a thin ridge formed by a row of small plates ; the 
lateral membrane is broad, thin, and pale yellow, running straight 
across, from the ventral end, at right angles to the dorsal portion, and 
then folding back upon itself, joins the dorsal part of the odontophore 
farther back, near its middle; beyond this point it is very narrow and 
rolled in. Length of the dorsal portion, 19""; of the ventral, 9; 
breadth of the dentigerous zone, anteriorly, 5°"; breadth of mar- 
ginal membrane, anteriorly, 7™™. 
The median teeth are broad, with three stout points, the middle 
one nearly twice as long as the lateral; the inner lateral teeth are 
much longer, with one long stout point and a short denticle on the 
outer side, below the middle; the two outer rows have simple, long, 
and rather stout, curved teeth, those of the outermost row a little 
longer and narrower than the others. The teeth differ decidedly from 
those of S. megaptera in the shortness of the lateral denticles of the 
median and inner lateral teeth; moreover all the teeth are stouter and 
less acute, 
The pen resembles that of Ommastrephes; it is long, widest ante- 
riorly, bordered by strong ribs, obtusely pointed at the anterior end, 
gradually narrowing to the very narrow slender portion, about three 
inches from the posterior end, beyond which there is a thin margin, 
which expands into a lanceolate form, widest at 1°25 inches from the 
