8 HOYLE, Genera of Recent Dibranchiate Cephalopoda. 



[A narrow lanceolate shell present ; the direct connec- 

 tion between the head and mantle narrow (not 

 exceeding about 8 mm.) ; left dorsal arm hecto- 

 cotylised Sepiola. 



zZA 



29.-: 



Shell entirely absent ; dorsal connection wide, about 



15 mm , 29 



Suckers in two rows on the arms and in four rows on 

 the tentacular club 30 



Suckers in four rows on the arms and in sixteen or 

 more rows on the tentacular club Euprymna. 



,^Arms only connected at the base by a narrow umbrella ; 

 ventral margin of the mantle not produced forwards 

 under the head ; fins moderate ; left dorsal arm 

 hectocotylised Inioteuthis. 



3°* \ Interbrachial umbrella extending half way up the 

 arms ; ventral surface of mantle with a brown 

 shield-shaped patch, margin produced forwards ; 

 fins very large ; both dorsal arms hectocotylised. 

 \ Stoloteuthis. 



'Fins near the hinder end of the body, large ; ventral 

 mantle margin moderately produced not covering 

 the funnel ; right dorsal arm hectocotylised and 

 fused at its base with the second tJeteroteuthis, 



Fins very large, midway along the mantle ; ventral 

 mantle margin much produced covering the funnel ; 

 distal portion of the arms with diminutive suckers 

 on elongated stalks Nectoteuthis. 



Fins at the hinder end of the body ; very large in 

 proportion to the body Promachoteuthis, 



3i-i 



32.i 



Fins at the sides of the body ; small in proportion to the 

 body 33 



