NOTES OX OEGOI'SID CEPIIALOPODS FOUND IN JAPAN. 



Mantle-opening wide and free along the entire margin, of which the dorsal 

 median margin protrudes a little forwards, forming a short but broad 

 triangular projection ; lateral margins concave ; ventral margin projecting 

 beneath head, its median region slightly curving backwards. Fins very 

 thick and large, the length being about equal to 5/6 of mantle-length, and 

 taking both of them together, are nearly circular in shape, though 

 acuminated posteriorly and slightly cmarginated at the anterior attachment. 



Head very large, being a little broader than mantle-opening ; siphonal 

 groove rather shallow, smooth within, and without sharp boundary edge 

 at the anterior end. Eyes unequal in size and shape ; right eye of usual 

 shape, the eye-opening provided with a shallow sinus in front ; left eye of 

 a peculiar shape, with large eyeball and wide eye-opening twice as broad 

 as that of the right side. Neck smooth, but with a minute semicircular 

 membranous papilla on each side. 



Siphon nearly conical, short, reaching to about the middle of head ; 

 dorsal siphonal connective ligaments in 2 pairs, entirely embedded in 

 integument. Siphonal resisting cartilage oval in shape, becoming a little 

 wider backwards, with a deep median groove which also becomes wider 

 and deeper posteriorly ; mantle cartilage about as long as the siphonal and 

 of a crest-like shape, as high as long, and becoming higher backwards. 

 Nuchal cartilage of a bisquit-likc outline, narrowed in the middle, and 

 provided with a longitudinal median ridge with a groove running along 

 the crest. Buccal membrane thick and fleshy with finely wrinkled inner 

 surface, with eight connective ligaments and with seven somewhat indistinct 

 ribs and marginal projections. Outer lip thin ; inner lip thick, with papillate 

 margin. 



Arms long and unequal, the formula of their length being 4>2)>3)>i ; 

 longest arm a little shorter than mantle-length. First and second arms a 

 little flattened laterally, with a keel along their outer surface. Second 

 and fourth arms quadrangular in section, with a web along their ventral 

 outer edge. Protective membranes of all arms as broad as length of suckers. 

 Suckers nearly semicircular, with thin and narrow horny edge, which is 



