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which occur in such myriads as to give name to the form- 

 ation in which they are contained, are pointed out as 

 requiring still further examination with respect to their 

 original mode of existence, and more satisfactorily to prove 

 that they were not of animal origin. 



Confining ourselves to the univalve multilocular shells 

 which may be examined by the naked eye, it still remains 

 to advert to some of those shells which have been marked 

 by M. de Montfort with generic designations, and to notice 

 the claims which they may possess for such distinction. 



Angulitlies. A multilocular shell, with the characters of 

 nautilus, the mouth being of a triangular form. Triangular 

 nautilite of Havre. 



Bellerophron. The shuttle nautilus. Le nautile de prime. 

 Sonnini. 



Oceanie. Le petit nautile ombiliquc. Favanne. 



The distinctions marking these shells can hardly be con- 

 sidered as more than specific characters ; and it is with still 

 less reason that the species of ammonites now distinguished, 

 by De Montfort, by the generic names aganides, pelagus, 

 canthropes, simplegades, and amalthea, are removed from 

 their original genus ; since, if such differences as these 

 exhibit are to be admitted as generic, with equal right 

 generic titles might be claimed for many more of the hun- 

 dreds of different shells which are numbered under the 

 genus ammonites. 



Several of the additions which this author has made to 

 the genera of straight multilocular shells appear to be founded 

 on insufficient or even erroneous assumptions. 



Paclites is a fossil which Mr. Walch had described as 

 a belemnite, having a small circular hole at the extremity of 

 a curved point, and, beneath this, a long narrow opening. 

 This is described, by M. de Montfort, as terminating in a 

 stellated sphincter, and having a plaited lateral slit ; which 

 does not accord with that of Mr. Walch, who both describes 



