110 AMERICAN JOURNAL 



He also remarks, in his subsequent description of Ji. suhglo- 

 bosa, "It is a second species of my proposed genus Ancvloivs.''' 



Mr. Say never described \\\s, genus; but the above citation and 

 description of two species, both of which are well known, and 

 whose identity with his descriptions has never been ques- 

 tioned, entitle his generic name to be received as authority. 



Rafinesque published the following genera which have been 

 referred to StrejyomatidfV : — 



" Pleurocera, Raf. (Jour de Phys. Bruxelles, vol. Ixxxviii. p. 

 423, 1819.) Shell spiral, oval, or pyramidal, of numerous con- 

 vex volutions. Aperture obliquely oblong, the base prolonged 

 and twisted, sharp above. Outer lip thin, the inner lip ap- 

 pressed, twisted, without umbilicus. Animal with a membrana- 

 ceous o]ierculum. 



"Head proboscidiform, inserted on the back; tentacles two, 

 lateral, subulate, sharp, with eyes at their exterior base. 



"Family of N<.ritacea. Species numerous, of which I have al- 

 ready twelve, all fluviatile, from rivers and creeks, as well as 

 the following genera."* 



By some strange mistake, this genus is referred by Messrs. 

 H. & A. Adams to Vivipara. 



Eafinesque published several species ; one of which, P. ver- 

 rucosa^ is identical with Lithasia nupera, Say, and therefore be- 

 longs to an entirely different group. Others, however, are evi- 

 dently closely related to M. canaliculata, Say, and J/, elevata, 

 Say, The genus is certainly well characterized, and clearly 

 includes those shells which Mr. Swainson has subsequently dis- 

 tinguished as Ceriphasia, and Mr. Lea as Trypanostoma. 



In the same Journal, (p. 26,) Eafinesque described a genus 

 " Leptoxis " as follows. '' Leptoxis. Differs from Lymnula by an 

 oval shell, inflated, the spire of two or three whorls ; aperture 



* Eafinesque previously described Pleurocera in a short paper published in 

 the American Monthly Magazine and Critical Review, iii. p. 354, 1818 

 (Binney ifc Trj^on's Edit, of Eafinesque, p. 22,) as follows : — 



'■ Shell variable oboval or conical, mouth diagonal crooked, rhomboidal, 

 obtuse and nearly retiexed at the base, acute above the connection, lip and 

 columelle flexuose entire. Animal with an operculum membranaceous, 

 head separated from the mantle inserted above it, elongated, onetentaculum 

 on each side at its base, subulate acute, eyes lateral exterior at the base of 

 the teutacula." 



This description was doubtless intended for all the elongate species of 

 Melanians from the Ohio River then known to him, but he afterwards 

 amended it as above. 



In his '• Enumeration and Account" (Binney & Tryon, p. 67J Rafi- 

 nesque describes several species of Pleurocera, and remarks, " My G. Pleuro- 

 cera, 1819, is perhaps a S. G. of Melanin, but the animal is difierent, with 

 lateral feelers ; the shell is always conical oblong, with the opening oblong 

 obhque acute at both ends, columella liexuose twisted;" and, further, '' I 

 leave the name of Melania to the shells with opening obtuse at the end ; or 

 they may form the S. G. Ambloxis.^'' 



