NOTES OX THE JAPANESE MYOPSIDA. 605 



List of specimens examined. 



Specimens 



Locality 



Date 



Where preserved 



i£ 



Sagami Bay 



Feb. 16, 190 1 



Sci. Coll. 



x£. 3$- 



Satsuma 



April 30, 1906 



do 





Misaki market 



Dec. 1 90S 



do 





Uodzu, Etchû 



April 30, 19 1 3 



Agr. Coll. 





Namerikawa, Etchû 





Fish. Inst. 

 Namerikawa 



»SÄ. 46^. 



Oshoro, Hokkaido 



July I, 1913 



Agr. Coll. 



138 j'uv. 



Namerikawa, Etchû 



Aug. is, 1913 



do 



6£, 2J£ 



Tòkyo market 





Sci. ColL 



The present species is one of the commonest of this genus. It 

 is distributed from Kiushu to Hokkaido, in both the Sea of Japan 

 and the Pacific Ocean. 



In mature male specimens, the mantle bears a distinct median 

 ridge on the ventral surface. The length of mantle becomes pro- 

 portionately greater as the animal grows older, as will be seen from 

 the following table : 



Mantle-length 



Mantle-breadth 



Fin-length 



Head-length 



Length of 

 Longest arm 



mm 

 91 (1) 



mm 

 22 (O.242 — ) 



mm 



50 (O.549 + ) 



mm 

 14 (O.154-) 



mm 



34 (0.374- ) 



150 (I) 



30.5 (O.203 + ) 



86 (0.573") 



23 (O.I35-) 



51 (0.340) 



2IO (I) 



37 (0.176+) 



128.5 (0.612 — ) 



21 (O.IOO) 



5S (0.276 + ) 



280 (I) 



40 (O.I43-) 



1S2 (0.650) 



23.5 (O.084 -) 



66 (0.236 — ) 



(I) 



43 (0.130) 



225 (0.681) 



33 (0.100) 



75 (0-227) 



