I' RE PACK. V 



arc nientionecl by Mr. Parkinson, in liis third volinne of the 

 Organic Remains of a Former World, as being pu})lislied in 

 some other works; either in the Jouriiul (VHistoire NaliircUe, 

 or Memoires de la Societe d 'Histoire Naturelle de Paris, or 

 the Annaks du Musetim d'Histoire Naturelle, or the finite 

 des Memoires stir les Fossiles des Environs du Paris, &c. But 

 not having' an opportmiity of referring to those works, the 

 descriptions of those genera, together with four or five formed 

 by Mr, Parkinson, are taken from his " Organic Remains of 

 a Former World." In order to elucidate the descriptions of the 

 genera both of Linnaeus and of Lamarck more perfectly than 

 can be done by verbal descrij)lion, it has been judged neces- 

 sary to add some plates. The figures are generally of those 

 shells to which Lamarck refers as examples. It is hoped that 

 those parts on which the generic characters depend are di- 

 stinctly shown. In some cases where the shells were not easily 

 procured, or \a ere very common, or the genus so small that 

 perhaps only one species is known, the figures are omitted ; 

 but in this case a reference is given to a plate in some 

 work of credit. Those which are introduced as examples 

 of the principal genera of the recent shells are intended to 

 make the Work more complete ; but if a figure of a shell of 

 eveiy genus had been given, it would have added much to the 



