14S 
M, SASAKI. 
that all the aquiferous pores between the first pair of arms, as well as between 
the first and second arms of both sides, are continuous with each other. Be- 
sides the pores of the dorsal side, there are also found pores between the 
lateral arms, as well as between the third and fourth arms, but in some speci- 
mens, those between the lateral arms of the left side are not found. 
The radula 
comprises seven 
series of teeth ; 
the median tooth 
being tricus- 
pid, the lateral 
bicuspid and 
both marginals 
unicuspid ; the 
outer marginal 
teeth are very- 
narrow^, the length 
being equal to the combined length of the two succeeding median teeth 
(text-fig. 4). 
The gladius is very narrow, without lateral vanes, but at the posterior 
end, there is a slightly expanded portion, the length of which is about one- 
fifth of the whole, and which forms a cone posteriorly (PI. IV, fig. 13). 
On the ventral surface of the head, a j^aler macula is found at the base of 
each ventral arm, and on the ventral surface of the mantle, there is also 
a pair of longitudinal zones of the same character, which runs along the 
whole length of the mantle, dividing laterally the same surface into three equal 
areas, and, curving slightly outwards anteriorly, enlarged at the extreme an- 
terior ends. Those maculae and zones seem, judging from their histological 
structures, to be phosphorescent organs. When the mantle is flayed, a long 
white substance which has always another brownish substance along the 
median line, appears along each paler zone. The white substance is not con- 
Fig. 4. — SyinplectoteiUhis luiiiiiiosa sp. nov. camera drawing 
of radula, X 60. 
