10 HoYLE, Genera of Recent Dibranchiate Cephalopoda. 



Some of the suckers modified into hooks 40 



No hooks 56 



39 



40 



{Suckers or hooks in four rows on the arms. 

 (GoNATiD^) Gonatus. 

 Suckers or hooks in two rows 41 



/'Thesessilearmsbear only suckers. (ONYCHOTEUXHiDyE) 42 



4^''\The sessile arms bear hooks, usually with suckers also 

 I at the tips (Enoploteuthid^) 47 



42. 



'Body soft and gelatinous ; tentacles rudimentary with 



bulbous knobs Chaunoteuthis. 



.Body firm and fleshy, tentacles present 43 



(Tentacular club with hooks on the central part in two rows 44 

 Tentacular club with hooks or suckers in four rows 45 



Pen with a very strong keel, visible through the integu- 

 ment of the back as a well-defined dark streak ; 

 lateral wings of the pen clearly d.&'SQ\.o^Q.d...Onychoteuthis}^ 



44-<! 



45- 



46.< 



Pen with a slight keel, not visible through the integu- 

 ment ; lateral wings absent or rudimentary 



Ancistroteuthis. '^ 



'Central part of the club with two central rows of hooks 



and two lateral rows of suckers Teleoteuihis. 



^ Club with four rows of hooks or suckers 46 



'Mantle with shagreen-like tubercles ; arms with rudi- 

 mentary swimming-web Tetronychoteuthis.^ 



Mantle smooth ; arms with a swimming-web provided 

 with transverse ribs ; buccal membrane darkly 

 coloured Lycoieuthis}^ 



