Vll 



Oriental Melanians;* but he did not at that time 

 apply the results of his examinations to their obvi- 

 ous separation into two families. 



Mr. Isaac Lea in 1862 proposed a new genus of 

 Melanians, Gon(ohasis,f wdiich, w^ith other genera 

 previously admitted, and including Melania, Lam., 

 he still continued to regard as belong-ino- to the fam- 

 ily Melanlidce, although in a foot-note he writes, "I 

 very much doubt if w^e have a single species in the 

 United States which properly belongs to this genus." 



Mr. Theodore Gill, in a recent paper on the classi- 

 fication of our fluviatile Mollusca,± assio;ns the fol- 

 lowing characters to the fomily llelanUdce: — 



"Teeth of lingual membrane, 3- 1-3; gills con- 

 cealed; rostrum moderately produced and entire or 

 simply notched ; foot not produced be}- ond the head ; 

 branchia3 uniserial ; lateral jaws present. 



"Aperture of shell acuminate behind ; generally 

 channelled at front ; size moderate. 



"The flimily of llelaniidce is here restricted to 

 exclude Fa mius, Montford {^= Pyrena,\j?a\\.,) Me- 

 lancdria, Bowditch, 3felatoma, Sw. (=r Clionella ? 

 Gray), Melano2:)sis, Lam., Vihex, Oken, and Hemi- 

 sinus, Sw. These appear to belong to a distinct 

 family, equally distinguished by the projecting foot 

 of the animal and the notch of the aperture of its 

 •shell. 



"The family may be named Melanopidce. 



" The other genera or subgenera that have been 

 proposed scarcely appear to exist in nature. * * 



"Tlie American Melanildce form a peculiar sub- 

 family — Cerq^hasincv,.'' 



Subsequently, in a foot-note,§ Mr. Gill mentions 

 the reason which caused him to make the above 



*Araer Jour. Sjieu:o, xli, 1, 21. Icon. Encyc. (Am. Ed.), ii, Mol- 

 lusca. p. 84. 



t Proceed. Acad. Nat. Sciences, Ma.y, 1802. 



j Systematic Arraiiircmcnt of tlio Klollusiis of tlio Family Vivipa- 

 rida;, and otliers. luhabiling the United States. — Proc. Acad. Nat. Sci., 

 p. 6'6y Feb., 1SC3. § ihid, p. ;jj. 



