298 



MELANIIXiE. 



Species of Ceripliasia. 



acuta, Lea. 

 Alexandrensis, Lea. 

 anuulifera, Conr. 

 canaliculata, Say. 

 elongata, Lea. 

 exarata, Lea. 

 Haleiana, Lea. 

 Kirtlaudiana, Lea. 

 lugubris, Lea. 



lutosa, Gould. 

 Ordiana, Lea. 

 regiilaris, Lea. 

 spurca, Lea. 

 subularis, Lea. 

 sulcosa, Lea. 

 symmetrica, Haiti. 

 Vainafa, Gould. 

 ' Virgiuica, Gmel. 



Genus PACHYCIIEILUS, Lea. 



Operculum suborbicular, of several whorls. 



Shell fusiformly conical, smooth, solid ; aperture ovate, 

 entire anteriorly ; columellar lip thickened posteriorly ; 

 outer lip thick. 



E:k. p. Isevissimus, Soicerhy, pi. 31, fig. 7. Opercu- 

 lum, P. corvinus, Morelet, fig. 7, a, 7, b. 



The chief peculiarity of this genus is the thickened 

 outer lip ; it differs from Melanopsu in having no sinus 

 at the fore part of the aperture, and from Melania in 

 having a callous columella. The operculum has the 

 nucleus subcentral, and is composed of two or three 

 spiral revolutions. 



Species of Pachycheihis. 



amoenus. Morel. 

 corvinus, Morel. 

 dubiosus, Say. 



ferrugineus. Lea. 

 grapliium, Morel. 

 ludiorum, Morel. 



