IX 



The publication of Mr. Gill's paper redirected 

 Prof. Haldeman's attention to the subject, which he 

 had left unfinished in his investigations at an earlier 

 period ; and the result is the publication of a short 

 but important paper in the Proceedings of the Acad- 

 emy of Natural Sciences, September, 1863, entitled^ 

 " On Strepomatidae as a Name for a Family of Fluvi- 

 atile Mollusca usually confounded with Melania," 

 wherein he finally separates our species as a dis- 

 tinct family, remarking that the Oriental Melanians 

 are not so nearly allied to ours as they are to the 

 Cerithiadce — with which conclusion we cordially 

 agree. 



We have, therefore, adopted the name Strepoma^ 

 tldce as indicating a distinct family, in preference to 

 the prior name of Ceriphasince, the adoption of which 

 would still leave our species in connection, as a sub- 

 fiimily, with shells to which they are not at all closely 

 related. 



In endeavoring to eliminate, from the rather con- 

 fused synonymy, generic and subgeneric groups of 

 Strepomatidm, some difficulty is encountered at the 

 threshold, on account of the various opinions held 

 by the different naturalists who have studied them, 

 regarding the relative importance which should be 

 assigned to various characters of the shell, in consti- 

 tuting these divisions. 



The genus Hemisinus, Swainson {^Basistoma, Lea), 

 belongs to Mr. Gill's family 3Ielano2ndce. The little 

 Paludomus hrevis, D'Orb., of the West Indies, is 

 apparently the American representative of an exotic 

 genus ; the large tuberculate Melanians of Central 

 America, and the smooth Pachycheili of that country 

 and of Mexico, probably do not belong to our family 

 StrepomatldoB. 



Thus the range of the species of the family may 



also, and with geographical distribution, believing, however, that other 

 and more important distinctive characters will reward the industry and 

 skill of some future malacologiat. 



