SEPIA. MOLLUSCA. 15 



C. vitrea, Lam. (Patella cmla/a, Lin.) Shell thin, hyaline, trans- 

 versely sulcate ; the back furnished with a dentate keel ; spire 

 conical, attenuate ; the apex very small and involute ; the aper- 

 ture narrowed toward the keel. Inhabits the Southern Ocean. 

 D'Argenv. App. pi. 1, fig. B. 



C.fragilis, Lam. Shell thin, hyaline, longitudinally striated; no 

 dorsal keel. Inhabits the African seas. Lam. vii. 674. 



C. Cymbium. Shell minute, somewhat conical, thin, grayish white ; 

 the apex obtuse and curved ; transverse rugee decussating the lon- 

 gitudinal striae. Inhabits the Mediterranean. Lam. vii. 674. 



ORDER II.- CEPHALOPODA. 



Mantle in the form of a bag, containing the lower part of the 

 body ; head protruding from the bag, crowned with inarti- 

 culated arms, furnished with cups or suckers, and surround- 

 ing the mouth ; two sessile eyes ; mouth with two horny man- 

 dibles ; three hearts ; the sexes separate. 



The animals of this order naturally arrange themselves under three divisions, which 

 are as follows : 

 I. NAKED CEPHALOPODA: no shell, either internal or external II. MONOTHA- 



LAMOUS TESTACEOUS CEPHALOPODA: the shell unilocular, entirely external. 



III. POLYTHALAMOUS TESTACEOUS CEPHALOPODA: the shell multilocular, 



subinternal. 



DIVISION I. CEPHALOPODA SEPIARIA. 



No shell, either internal or external ; but with a solid, free, cal- 

 careous or horny substance contained in the interior of the 

 body. 



The Sepiaria are marine animals, some of which creep along the bottom, and 

 others swim at large. They are all destitute of shell. Their body is fleshy, half 

 inclosed in a muscular bag, from which their fore part and head protrude. The 

 head is crowned by tentacular arms, arranged round the mouth, and furnished with 

 cups or suckers. With these arms they seize their prey and bring it to their cen- 

 tral mouth or beak. They are sometimes of large size. The Sepiaria emit when 

 pursued a dark liquor, which has been conceived to favour their retreat; and from this 

 liquor it is said the best China ink is prepared. The ancients also sometimes used 

 this fluid as writing ink, and esteemed the flesh of the animal as a delicacy. 



Gen. 1. SEPIA, Lam. 



Body fleshy, depressed, contained in a bag, which is obtuse be- 

 hind, and margined on either side in its whole length by a 

 narrow fin ; a free, calcareous, spongy, and opaque bone, in- 

 cluded in the body near the back ; mouth terminal, surround- 

 ed with ten arms furnished with cups, of which two are pe- 

 dunculate and longer than the others. 



The spongy cretaceous body found in the interior of these animals near the back 

 is of an elliptical or oval form, thickest in the middle, and thin and edged on the 

 sides. In the centre of the arms which surround the head is the mouth of the ani- 

 mal, a circular orifice more or less fringed, with two hard corneous jaws, similar in 



