102 AMERICAN JOURNAL 



Genus Ceeithidea, Swainson. 



Clavate, cerithiform ; aperture subemarglnate. 



Subgenus Ceeithidea, Swains. 



Shell liglit; decollated ; outer lip semicircular, dilated by 

 a flattened border; aperture emarginate. C. lineolata, 

 Griff. Cuv., t. 14, f. 4. G.fragilis, Ihid. t. 82, f. 12. 



(= POTAMIDES.) 



Subgenus Ceeiphasia, Swains. 



Cerithiform; outer lip thin, dilated at the base; aperture 



small, slightly emarginate, without any internal groove; 



inner lip thin. C. sulcata, Sw., fig. 38. Founded on 



certain Ohio shells resembling Cerithidea? 



It will be noticed that in the above classification Melafusus 



is a subgenus of Melanopsis, which belongs to the family 



Melanopidse, while Geriphasia is a subgenus of Cerithidea, 



which includes shells belonging to the family CeritMidse\ 



Dr. Gray (Proceed. Zool. Soc, London, 1847, p. 153) makes 

 the following division of his subfamily Melaniaina, which in 

 many respects is very correct. He separates the exotic genera 

 from the American, and of the latter quotes the following : — 



Anculotus, Say, 1825. 



Anculosa^ Swains., 1840 — A. prsemor&a, Say. 

 Melanopsis, sp., Moricand — M. crenocarina* 

 Anculosa, sp., Anthony — Anc. ruhiginosa. 

 Melania, sp., Say — Melan. ohovata. 



Melatoma, Anthony, 184- ? not Swains. 1840. 



Melat. altilis, Anthony. 



lo. Lea, 1832. 



Fusus, sp.. Say, 1825. ] -n. n ■ .-t a 



ir 7 J- c • 10 1A } -t'ltsus nuviatclis, bay- 



Mela/iisus, Swams., 1840. j -^ > j 



Melania, sp., Say — ilieZ. armigera^ Say. 



Ceeiphasia, Swains. 1840. 



Gray, Syn. 1844. 



3Ielania, sp., Say — Geriphasia sulcata, Swains. 



? Telescopella. 



Melania, sp., Say — Mel. undulata, Say. 



* = Verena, H. & A. Adams : certainly not an Anculosa. — T. 



