CEPHALOPODA. 



521 



which are concave externally and perfo- 

 rated by a marginal and ventral siphon. 



Genus BELEMNITES, Lamarck.* 

 Fam. 3. SEPIAD&, Cuttle-fishes. 



Animal, body oblong, depressed, with two 

 narrow lateral fins extending its whole 

 length, 



Shell internal, lodged in a sac in the back 

 part of the mantle, composed of an ex- 

 ternal calcareous apex or mucro, of a 

 succession of calcareous laminae with 

 intervening spaces filled with air, and 

 supported by columns, but not perfo- 

 rated by a siphon, and an internal horny 

 layer, corresponding to the anterior 

 horny sheath of the Belemnites. 



Genus SEPIA, Cuv. 



The character of the family is also that of 

 the single genus at present composing 

 it; we may, however, add under this 

 head that the mantle is free at its an- 

 terior margin ; and that the acetabula 

 are supported by horny hoops with the 

 margin entire, or very minutely denti- 

 culated . 



Ex. Sepia officinalis, Linn, the common 

 Cuttle-fish. (Fig. 207.) 



Fig. 207 



Fam. 4, TEUTHIDM* Calamaries. 



Animal, body sometimes oblong and de- 

 pressed, generally elongated and cylin- 

 drical ; with a pair of fins varying in their 

 relative size and position, but generally 

 broad, shorter than thebody,and terminal, 



Shell internal, rudimental, in the form of 

 a thin, straight, elongated, horny lamina ; 

 encysted in the substance of the dorsal 

 aspect of the mantle. 



A . Funnel with an internal valve, and arti- 

 culated at its base to two ventro-laterat 

 cartilaginous prominences of the mantle. 



Genus SEPIOTFUTHIS, Blainville. 



Body oval, flattened, with narrow lateral 

 fins, extending its whole length ; ante- 

 rior margin of the mantle unattached. 

 Horny hoops of the acetabula with den- 

 ticulated margins. Gladius, or rudi- 

 mental shell, long and wide. 



Ex. Sepioteuthis loliginifbrmis, Ruppel. 



Genus LOLIGO, Cuvier. 



Body elongated,.cylindrical, provided with 

 a pair of rhomboidal or triangular fins, 

 shorter than the body, and terminal, 

 their apices generally converging to a 

 point, and united to the end of the man- 

 tle; anterior margin of the mantle free. 

 Horny hoops of the acetabula denticu- 

 lated. Gladius long and narrow. 



Ex. Loligo vulgaris, Cuv. the common 

 Calamary or Pen-fish. (Fig. 208.) 

 Fig. 208. 



' Also the fossil genera, Actinocamar , Miller 

 Pseudobelns, Blainville. 

 VOL. I. 



The Calamary, Loligo vulgaris, Cuv. 

 * From the term revQos applied by Aristotle to 

 the ten-armed Malakia with an internal horny 

 plate or yladius. 



2 M 



