98 AMERICAN JOURNAL 



1. Classification. — Swainson, who may be considered the 

 originator of the modern system of classification of the Mol- 

 lusca (as h^ was the first general conchologist who, breaking 

 through the trammels of Lamarckian nomenclature, inaugura- 

 ted the work since so boldly and succoBsfullj'- continued by Dr. 

 Gray and Messrs. 11. & A. Adams.) had, unfortunately, very little 

 knowledge of the affinities with the other Mollusca, of the so- 

 called Melanians inhabiting both America and the Old 

 AYorld, since he has confounded them with marine shells 

 under his family Turhidse ; but, notwithstanding this error in 

 the disposition of the whole group, he had the sagacity 

 to separate into numerous, and generally well-characterized, 

 genera, the incongruous materiel which Lamarck had allowed 

 to remain under one generic name, — Melania. 



Messrs. H. & A. Adams* approach more closely to the 

 present ideas of conchologists relating to this subject, by sepa- 

 rating from, but placing in close neighborhood to, the Cerithiadse, 

 their family Melaniidsc, of which they admit two subfamilies, 

 Melaniinse including those shells with "aperture simple in 

 front, without a distinct notch," = various genera of Melanians ; 

 and a second subfamily, characterized by a notched aperture 

 to the shell, including Melanopsis, Lam. Dr. Gray, the only 

 other recent systematist who has investigated the subject,t 

 adopts a family Melaniadse, including the subfamilies Ris- 

 soaiiia, Ilelaniaina^ Triphorina^ Scalarina, and Litiojnna. with 

 a heterogeneous assemblage of marine and fluviatile genera; 

 the Melaniaina comprising all the genera of American and 

 exotic Melanians, the Cerithians, and the shells which I 

 recently separated under the family name of AinnicoUdde. 



It is strange that neither European nor American concholo- 

 gists who have studied this family have availed themselves 

 until quite recently of the obvious differences, both in shell 

 and animal) between the American and Oriental forms, for 

 their complete separation, notwithstanding the fact that Prof. 

 Haldeman showed our Melanians to have a plain or entire 

 margin to their mantle, whilst the Oriental species had the 

 mantle-margin fringed, thus allying the latter more closely 

 with the Cerithians than with the so-called American Mela- 

 nians. 



Dr. Brot, a gentleman who has devoted much attention to 

 the Melanians, remarks:}: that the generally adopted classifica- 

 tion of the family is verj^ confused and uncertain, but does 

 not attempt to propose a new one. 



* Genera of Recent Mollusca, i. 293. 



t List of the Genera of Recent Mollusca, Proceed. Zool. Soc, London, 

 1847. 

 X Cat. syst. des Especes qui composent la Famille des Melanien?. 



