29V 
A. E. Verrill — North American Cephalopoda* 
die; posteriorly much larger, with a long tubular cone. This re- 
markable genus differs widely from all others hitherto described in 
the character of the tentacular arms and suckers. This, with the 
great size of the caudal fin, gives a very peculiar aspect to the species. 
Mastigoteuthis Agassizii Verrill. 
Bulletin Mus. Comp. Zool., vol. vi, pi. 1, fig. 1 ; pi. 2, figs. 2, 3-3 g, 1881. 
Plate XLVIII. Plate XLIX, figures 2, 3-3gr. 
Body elongated, round anteriorly; posteriorly tapering rapidly to 
the slender, acute, terminal portion, which is confluent with the cau- 
dal fin, to the tip. Front dorsal edge of mantle emarginate in the 
middle. Caudal fin very large and broad, transversely rhomboidal, 
obtuse posteriorly, its length, from origin to tip, about equal to half 
the combined length of the head and body. Eyes large, with thin 
lids, which appear to have had a distinct but very small sinus in 
front; pupils circular; iris brown, in alcohol. Sessile arms very une- 
qual ; ventral arms much larger and longer than the others, about 
equal to length of head and body; dorsal arms very small, scarcely 
one-third the length of the ventral pair; two lateral pairs nearly 
equal, decidedly longer and stouter than the dorsal pair. A delicate 
thin, marginal membrane extends along the arms, outside the rows 
of suckers, to the slender tips. Suckers small, in two regular rows 
on all the arms, subglobular, with small oblique apertures, surrounded 
by small horny rings, which have a nearly entire margin, and by sev- 
eral series of minute plates (Plate XLIX, fig. 3g). 
Basal web, between the arms, very small. In the smaller speci- 
men, which is a male, the right ventral arm is longer than the left, 
and the tip appears to have been flattened, and the marginal mem- 
branes seem to have been wider, with the edges infolded, so as to 
form a sort of furrow on the outer side, but the suckers are mostly 
gone, and it is too much injured to be accurately described. Ten- 
tacular arms long, more than twice the combined length of the head 
and body, slender, round, gradually tapering to the tip, like a whip- 
lash, the distal half of their length covered with very numerous, 
crowded, minute, pedicelled suckers (fig. 3d), which cover nearly the 
entire surface along the terminal portion, leaving only a narrow naked 
line along the back, but farther from the tip this naked space becomes 
gradually wider and the band of suckers narrower, and after these 
crowded bands of suckers cease, scattered suckers, placed mostly two 
by two, extend for some distance along the proximal part of the arms. 
The suckers of the tentacular arms are so small that their form can- 
