ON THREE INTERESTING NEW OEGOPSIDS FROM THE BAY OF SAGAMI. 133 
but short, being about as long as the siphonal ones. 
The arms arc subequal and long, the longest arm being about twice as 
long as the mantle-length, and the order of length seems about 3>2 > i >4, 
though the extremities of some arms are broken in the type specimen. They 
taper gradually towards the extremities and are nearly quadrangular in section, 
the outer surfaces being provided with neither webs nor keels ; but three 
dorsal pairs of arms have, along their median lines, a series of horny tubercles, 
details of which will be given subsequently. The third pair of arms has a 
short semilunar web in the middle of the outer surface. 
The buccal membrane has seven ribs and marginal projections, as usual 
in the family Histioteuthidae, and three dorsal ribs out of the seven are con- 
nected by double ligaments with the lateral sides of the bases of arms, the 
remaining four being attached by only a single ligament. The inner surface 
of the buccal membrane is finely wrinkled and of a purplish color. 
The umbrella and protective membranes of the arms occur nearly in the 
same way as those of M. koylci Pfeffer. The membranes of the umbrella 
between the two dorsal pairs of arms are fairly wide, extending about six or 
seven mm. up from the bases of the arms, while between the lateral arms, as 
well as between the third and fourth arms, they are very narrow, and between 
the ventral pair they are entirely wanting. 
The protective membranes of three dorsal pairs of arms are of the usual 
breadth equally on both sides of the sucker-bearing surface, except at the 
proximal parts of the arms where they widen, making connective membranes 
between the bases of the arms, and imitating the umbrella as it occurs in M. 
hoylci, and the membranes of the specimen now before me extend about 
thirteen mm. up from the bases of all the arms, all the protective membranes 
of the ventral pair being very narro^v. 
The arm-suckers also resemble those of M. hoylci in shape and arrange- 
ment. They are small and globular, arranged clearly in two series. These 
two series, in the three dorsal pairs of arms, from their bases to a point about 
half-way to their tips, are widely separated, the distribution of the suckers in 
