CEPHALOPODA. 



1045 



13 



14 

 15 

 16 



17 



18 



1U 



20 



21 



LOLIGINID.E. 

 SEPIID.E 

 SEPIOTEUTHIS. 

 SEPIA. 



ONYCHOTEUTHIDJE 



ONYCHOTEUTHIS. 



17 

 19 



18 



23 

 24 



25 



21 > J 



Fins marginal, extending the whole length 



of the mantle ; body oval . . . . . . 14 



Fins terminal, together heart-shaped or 



triangular in form ; body cylindrical, 



more or less pointed behind 

 | A ha I'd cuttle-bone internally 

 \ A horny pen internally 

 No glandular pores on the mantle 

 I Some of the suckers modified into hooks . . 

 1 No hooks 

 Suckers or hooks in 2 rows ; the sessile arms 



bear only suckers 

 Pen with a very strong keel, visible through 



the integument of the back as a well- 

 defined dark streak ; lateral wings of the 



pen clearly developed 

 Funnel articulating with the inner surface 



of the mantle by a cartilaginous joint on 



either side ...... 20 



Funnel fused with the inner surface of the 



mantle on either side . . . . 26 



Animals of gigantic size, mantle 2 to 3 



metres in length ; tentacle with a fixing- 



apparatus consisting of alternating pads 



and suckers extending along the stem ; 



pen feather- shaped with a terminal cone ; 



siphonal articulation unknown .. ARCHITEUTHID^:; ARCHITEUTHUS. 



Animal of moderate size ; mantle-length 



not exceeding 0-7 metre, generally much 



less .. .... .. ..21 



Articulating facet at the base of the siphon 



an elongated pit, without a transverse 



groove ; articulating facet on the inner 



surface of the mantle a linear ridge with- 

 out any transverse ridge . . . . . . . . 22 



Articulating facet on the siphon subtri- 



angular ; facet on the mantle w ith longi- 

 tudinal and transverse ridge, _|_-shaped 



or (-shaped . . . . . . . . . . 24 



Numerous luminous organs on the ventral 



aspect of the body, siphon, head, and 



arms . . . . . . . . HISTIOTEUTHID.*: . . 23 



Horny rings of arm-suckers without teeth. . 

 Fins usually sagittate, broader than long ; 



siphonal cartilage with longitudinal 



groove, crossed by a posterior shorter 



transverse groove : thus, _|_ . . 

 Sucker- bearing portion of the tentacle ex- 

 tending more than half its length 

 Mantle fused with head in nuchal region ; 



no accessory fin ; arms with extremities 



normal. Tentacles (if present) with 



suckers only, no hooks . . . . CRANCHIIDA: . . . . 27 



Body fusiform, no phosphorescent organs 



on the eyes ; no chitinous tubercles on 

 the mantle 



HISTIOTEUTHID.E 

 CALLITEUTHIS. 



OMMASTREPHID^E 



OMMASTREPHES. 



25 



