Ö20 



.MADOKA SASAKI : 



of the right ventral arm. Arms in female subequal, the order of 

 their length being 2, I, 3,4; the second arm shorter than mantle- 

 length. Arm-suckers arranged in four longitudinal series in the 

 proximal part of each arm, and in two series in the distal part ; horny 

 ring entire. Tentacles thick and long, about twice as long as the 

 ventral length of mantle ; tentacular suckers arranged in eight 

 longitudinal series and in markedly oblique transverse rows ; their size 

 greatly unequal, four suckers in dorsal submedian series being much 

 larger than the rest ; horny ring of the smaller suckers with numerous 

 long teeth on edge. 



Shell lanceolate, with small discoidal outer cone at the posterior 

 extremity ; dorsal surface convex, with an arched median area marked 

 off on each side by a distinct groove ; ventral surface convex in the 

 anterior, and concave in the posterior parts, with a prominent ridge 

 along the median line ; last locular boundary of a V-like shape with 

 the pointed end turned backwards ; inner cone slightly developed. 

 Locular index about 40. 



Two -£ and four ^_ specimens were obtained by Prof. S. Watasé 

 at Choshi, Kazusa Prov., on August 18, 1906 (Sci. Coll.). Mantle- 

 length of largest male 235 mm., that of largest female 178 mm. 



Dimensions of typical male and female specimen (in alcohol), as 

 follows : 





Male 



Female 





mm. 



mm. 



Dorsal length of mantle 



220 



I47 



Ventral length of mantle 



170 



I16 



Breadth of mantle 







75 



Breadth of head 



75 



50 



Breadth of fin 



15 





Length of first arm 



420 



105 





210 



120 



,, „ third arm 



140 



90 



,, ,, fourth arm 



140 



70 



