MUSEUM OF COMPARATIVE ZOOLOGY. 113 
OPISTHOTEUTHIS Verritt, gen. nov. 
Body broad, depressed, closely united to the brachial web except at the 
posterior end, which projects slightly. Fins long, attached at about the middle 
of the body, near the dorsal surface ; bases wide apart, each supported by a 
distinct transverse cartilage. Siphon small, projecting slightly from beneath 
the posterior end of the body, and directed backward, with a very small aper- 
ture. Head as broad as the body ; eyes large. The lower surface of the head 
and body wholly attached to the brachial membranes. Arms subequal, united 
together to near their tips by a very broad, thick, soft web, which leaves only 
the inner surface of the arms exposed ; suckers in a single row, those toward 
the base of the arms largest. On each side and alternating with the suckers is 
a row of small, tapered cirri ; these commence in a rudimentary form between 
the first two suckers, and continue from there to the tips. 
Opisthoteuthis Agassizii VERRILL, sp. nov. 
Plate I. Fig. 1. Plate I. Fig. 1. 
The body is broad, depressed, rounded posteriorly, and with the head is 
wholly adnate to the web connecting the arms, except at the posterior end 
behind the fins, where it is slightly free and overhangs a little ; the siphon 
projects backward beneath the posterior end in the groove thus formed; the 
branchial opening appears to have been small, partially surrounding the siphon, 
but the membranes in this region are much mutilated, so that its form and 
extent cannot be determined. The fins are large, thin, wide apart, elongated, 
oblong ovate in form, the outer end bluntly rounded, each fin is supported by 
a separate internal cartilage, of which the inner end is broadest and thick, while 
the outer end extending into the free portion of the fin is much thinner, lanceo- 
late, tapering to a blunt point; this cartilage is situated much nearer to the 
posterior than to the anterior edge of the fin and does not extend much beyond 
its middle, leaving the terminal third thin and flexible. The head is about as 
large and as broad as the body ; the eyes are very large and occupy the entire 
sides of the head. As seen from above the arms are concealed except at the 
tip by a thick, soft web, which unites them together and unites them closely to 
the sides of the head and body. The integument of the entire upper surface is 
very soft and flabby, and appears to have been smooth, although it is much 
wrinkled in the alcoholic specimen; the web between the arms extends to 
near the end, leaving only about one fifth free, and this portion is bordered by 
a membranous fold along each side. The web consists of an outer and inner 
portion, separated by considerable thickness ; the inner membrane arises from 
the inner surface of the arms, which projects but little above it. The arms are 
rather large and moderately stout along the middle portion, much narrowed 
toward the bases, which are not in contact ; the free ends are rather slender, 
VOL. XI. —NO. 5. 8 
