15 



Long. 40 mill. ; larg. 16 mill. 



Nous avous annonce dans notre ouvrage sur les fossiles des environs 

 de Paris (tome II. page 105) que la Melanie souillee, si abondarament 

 repandue a I'etat fossile dans le bassin de Paris et en Angleterre, se 

 trouvait aussi vivante ; nous avions cite ce fait de m^moire, ayant vu la 

 coquille vivante, quelques annees auparavant dans la collection de 

 M. De Ferussac ; aujourd'hui que nous possedons aussi cette espece a 

 I'etat recent, nous en donnons une figure que Ton pourra facilement 

 comparer avec celles qui sout dans notre ouvrage ; on s'assurera par ce 

 moyen de I'identite des individus vivants et fossiles, et Ton s'apercevra 

 que I'individu figure ici est une vari^te a ajouter a celles qui sont 

 connues. II a quelques stries de plus vers la suture, et n'a sur chaque 

 tour qu'une seule strie transverse qui soit tuberculeuse. Nous renvoyons 

 pour le reste de la description, soit a notre ouvrage, dans I'endroit 

 precite, soit a I'article Melanie du Dictionnaire des Sciences Naturelles, 

 par M. Defrance. Patrie : les Phillippines. 



Juin, 1830. Dkshayes. 



Let me now, before instituting a comparative examination of the fossil 

 and recent shells, first compare the figures and desciiptions of Deshayes, 

 in compliance with his invitation. It will be seen upon making this 

 comparison that there are several points in which the recent differs from 

 the fossil shells ; the first of these is the form of the volutions, which in 

 the figure of the recent shell are represented as being wider in propor- 

 tion to their length, and more convex than in the figures of the fossil ; 

 the next is the suture, which is represented as much more deeply placed 

 in the recent than in the fossil, in which latter Deshayes says it is super- 

 ficielle'^ ; then the form of the aperture is represented in the fossil as 

 smaller and rounder than in the recent ; the appearance of a thickened 

 margin is also given to the figures of the fossil, while in the recent 

 figure the margin is made to appear thin and sharp-edged : next, in the 

 description the recent shell is said to have longitudinal ribs at the apex 

 fapice costatd ; costis longitudinalibusj and in the figure these longi- 

 tudinal ribs are made to extend more or less distinctly nearly over the 

 whole shell, but these ribs are neither mentioned in the description nor 

 do tiiey at all appear in any of the figures of the fossil varieties; then 



