DENTAL1UM. 449 



the resemblance of the foot to that of some of the bivalves, 

 combined with the similar character of its action, appear in 

 a striking manner to show its connection with the Con- 

 chiferse ; whilst by its oesophageal cerebral ganglions, and 

 completeness of the circulation, it has established its claims 

 as a Gasteropod. There are also traces of alliance with 

 some of the inferior classes ; the red blood and vermiform 

 configuration of the posterior part of the animal shows 

 some of the characters of the Annelides. ,, * 



There are some shells which may readily be confounded 

 with Dentalia. These are the testaceous tribes of Anne- 

 lides, of the genus Ditrupa. A slight constriction around 

 their orifices is usually an indication of their true nature. 



D. entalis, Linn. 



Porcelain white, lustrous, not at all striated : posterior end 

 ernarginated. 



Plate LVII. fig. 11. 



Dentalium entalis, Linn. Syst. Nat. ed. 10, p. 785, and ed. 12, p. 12b"3, in part ; 

 Fauna Suecica, ed. 2, p. 534. — Mont. Test. Brit. p. 494 (in 

 part only). — Maton and Rack. Trans. Linn. Soc. vol. viii. 

 p. 237. — Turt. Conch. Diction, p. 37, 40. — Johnston, Ber- 

 wick Club, vol. ii. p. 38, animal. — Macgil. Moll. Abe rd. 

 p. 200. — Brit. Marine Conch, p. 1. — Brown, Illiist. Conch. 

 G. B. p. 117, pi. 56, f. 7 (probably). 



Worn individuals of the succeeding species have so 

 generally been confused with the present one, that the 

 earlier synonyms of this shell are of difficult determination. 



Linnaeus, in the tenth edition of his Systema, confounded 

 the two species, but the expression " Isevi," added in the 

 twelfth, is more applicable to the northern shell. The 



* Clark in Annals Nat. Hist. ser. 2, vol. iv. p. 328. 

 VOL. II. 3 M 



