ON THREE INTERESTING NEW OEGOPSIDS FROM THE BAY OF SAGAMI. i 3^ 
being the anterior, and has a very narrow posterior portion ; the anterior 
margin is truncate, with neither projection nor emargination. The fins are 
long and are bothtogether cordate with pointed lateral edges, the post-lateral 
edges being arched, and attenuated posteriorly, vanishing at some distance 
(13 mm. in a male with 213 mm. mantle-length) before the extreme end of the 
mantle (PI. IV, fig. i). 
The head is as broad as the mantle-opening, with a sharp boundary 
edge behind. The eye-openings have, at a point a little below the middle 
of the anterior edge, a deep sinus, of which the dorsal margin is greatly 
thickened. The siphonal groove is fairly deep, being bounded by a distinct 
edge, the post-lateral portions of which, projecting a little, embrace the siphon 
laterally. The foveola in front is distinct, being bounded by a falcate fold pos- 
teriorly, but without any other folds either inside or outside. The olfactory 
crest of each side consists of one transverse and three longitudinal folds, the 
latter ones extending between the former and the posterior boundary edge 
of the head (PI. IV, fig. 2). 
The siphon, tapering a little forwards, extends generally to the middle of 
the head ; the collar-like portion of the base is free posteriorly around the 
viscera, except at the nape where it joins the skin. The siphon is connected 
with its groove, by two pairs of ligaments, one pair of which is dorsal and the 
other entirely lateral in position. From between the dorsal pair there pro- 
jects, in all the specimens examined, a muscular protuberance with a round 
head. 
The arms are thick, long, and of subequal length, the formula being 
3i=2>i>4; the longest arm is about half as long as the mantle. The 
first pair of arms is nearly quadrangular in section at the proximal halves and 
nearly cylindrical at the remaining distal halves. The second pair is also 
quadrangular either at the proximal parts or at the distal, and is provided, 
along the ventral outer edges, with a web as broad as its own protective 
membranes. The third pair is compressed laterally, being provided, along the 
whole length of the outer surfaces, with a very high keel, of which the highest 
