446 



DENTALIAD^. 



Although we place the singular genus of Gasteropoda, 

 which constitutes this family, in this place, as if it were a 

 transition onwards from Patella to the fissurated Limpets 

 — a position accordant with the view taken of its structure 

 by Deshayes, who first decided on its molluscan nature, — 

 we do so merely provisionally, and not without strong 

 misgivings : for the account of the anatomy of Dentalium 

 Tarmtiiwm, just published by Mr. Clark, in the " Annals 

 of Natural History," for November, 1849, throws so much 

 new light on its structure, that it might have been better 

 had we placed the group between Chiton and Patella. 



That the animal of the tooth-shell was not an Annellid, 

 w r as first observed by the celebrated Savigny ; that it was 

 a true mollusk, was first determined by Deshayes, and that 

 it should constitute a distinct order of Gasteropoda, to 

 which the name of Cirrhobranchia was given, was first 

 proposed by De Blainville. In the Memoir of Deshayes, 

 communicated to the Natural History Society of Paris, 

 in 1828, there is a very full account of the animal ; in 

 some very essential particulars, however, the French and 

 English malacologists are at variance. 



The shell of the Dentaliada is a cylindrical testaceous 

 tube, open at both ends, the anterior orifice being much the 

 wider. The animal is shaped like the shell, and so far as 

 its characters may be regarded as of ordinal or family 



