340 THE CEPHALOPODA 



Cheiroteuthis, d'Orbigny ; with suckers along the whole length of the 

 peduncle of the tentacular arms (Fig. 298, A). Doratopsis, Rochebrune ; 

 body much elongated, ending in a spine ; dorsal arms very short (Fig. 296) ; 

 Atlantic and Mediterranean. Histioteuthis, d'Orbigny ; the six dorsal arms 

 are united by a membrane ; the body covered with photogenous organs. 

 Histiopsis, Hoyle ; the membrane of the dorsal arms only reaches half- 

 way up the arms ; luminous organs present. Calliteuthis, Verrill ; no 

 brachial membrane ; luminous organs present. Grimalditeuthis, Joubin ; 

 the fin of each side is divided into two separate lobes : no tentacular 

 arms (Fig. 258). FAMILY 11. CRANCHIIDAE, Gray. The eight normal 

 arms are very short. The eyes prominent. The fins small and terminal. 

 Genera Cranchia, Leach; body bursiform ; sessile arms short; fins 

 entirely aboral. Loligopsis, Lamarck ; body elongated, conical ; tentacular 

 arms slender. Leachia, Lesueur ; tentacular arms aborted ; the funnel 

 without a valve (Fig. 298,0). Taonius, Steenstrup ; body elongate ; sessile 

 arms rather short; eyes pednnculated (Fig. 253). 



TRIBE 2. MYOPSIDA. 



. The members of this tribe are characterised by having a closed 

 external cornea, and by having only a single oviduct, viz. that of the 

 left side. The internal shell has no longer a distinct phragmocone, and 

 is calcified (Sepiidae) or simply chitinous. The Myopsida are more 

 littoral in habit than the Oigopsida. 



Fia. 298*'. 



Sepia officinalis, swimming, right side view, a, arms ; fi, fins ; fu, funnel. (After 

 Merculiano.) 



FAMILY 1. SEPIIDAE, d'Orbigny. Body wide and flattened ; fins 

 narrow and extending the whole length of the body (Fig. 298 6 **). Shell 

 calcareous and laminated, forming the " sepion." Genera Eelosepia, 

 Voltz ; a rudiment of the rostrum and phragmocone present ; Eocene. 

 Sepia, Linnaeus ; shell with a rostrum (Figs. 262, B, and 299) ; British. 

 Sepiella, Steenstrup ; shell without a rostrum. FAMILY 2. SEPIOLIDAE, 

 Leach. Body short, rounded at the aboral end ; fins rounded, inserted 

 on the middle of the length of the body. Shell chitinous, narrow 

 and shorter than the body, or absent. Genera Sepiola, Leach ; head 

 united to the mantle in the anterior (dorsal) region ; a fossorial British 

 genus. Rossia, Gray ; head not united to the mantle ; British. 



