142 
M. SASAKI. 
dorsal ones are always smaller than the more ventral. The suckers are near- 
ly semicircular with abroad aperture, but the larger ones, having a very deep 
cavity, are longer in profile than the smaller suckers, which are shorter, with 
bottoms raised up to the level of the aperture. The horny ring in the largest 
sucker has, along the whole margin, about twenty sharp, slightly recurved 
conical teeth of about equal length, their breadth being a little narrower 
than the interdental spaces. Those of the marginal suckers show nearly the 
same characters in denticulation as the largest one, but the teeth of the lower 
margin are distinctly shorter than those of the upper. Those of the distal 
and carpal suckers also have teeth resembling those of all the preceding 
ones in the upper margin, but the edges of their lower margins show an even 
contour, projecting slightly and forming narrow borders. 
The umbrella is very narrow. The buccal membrane has seven ribs, 
projections, and connectives, of which the dorsal-most is divided into two 
branches near the arm-bases, the inner surface being papillate. The outer 
lip is thin : the inner, thick and papillate. The so-called aquiferous pores 
between the arms and buccal membrane are four in number, between the first 
and second, and between the third and fourth, pairs. 
The radula comprises seven series 
of somewhat thick teeth, the median 
tooth being tricuspid, the lateral bicus- 
pid, and both the marginals unicuspid. 
The lateral teeth are about as long as 
the median, and the outer marginal a 
little longer than the combined length 
of the two succeeding medians (text-fig. 
3). 
The gladius is shorter than the mantle-length and is composed only of 
rhachis, lacking lateral vanes, but at the posterior part, narrow, wing-hke late- 
ral expansions from the rhachis are found, the length of which are about one- 
fifch of the whole length, making a shallow cone posteriorly (PI. IV, fig. 6). 
Fig. T,.—Ommastrcphes volatilis sp. nov. 
camera drawing of radula, X 60. 
