246 NEW MELANIDiE OF THE UNITED STATES. 



groups in the form of the fissura, the cut in the lip. In one group this fissura is deep 

 and direct, that is parallel with the suture or upper edge of the whorl ; in the other 

 it is not deep and is oblique to the suture. 



The observations of Dr. Showalter, in his letter accompanying the specimens, as to 

 the habits of the Schizostoma are well worth recording. He says, " this genus seems 

 only to flourish among the rocks, in waters flowing through the Carboniferous and 

 Primary Formations. It does not exist in the Black Warrior River at Tuscaloosa, 

 among the Carboniferous rocks, nor at Centreville in the Cahawba River, of the same 

 geological period. Prom the species described by you in the Transactions of the 

 Am. Phil. Soc, which you kindly sent to me, and whose habitat is given at Tusca- 

 loosa, I was led to examine that locality for them, but found none." It is important 

 to correct the errors of habitat of these (some four or five) species, which I described 

 about sixteen years since. "When the exact habitat of a species can be given it 

 ought always to be carefully put down. All the species referred to as existing at 

 Tuscaloosa came to me with that habitat, and now we learn that the genus does not 

 inhabit that part of Alabama. They were probably sent to my friend Dr. Budd, 

 who kindly sent them to me for description if new, from Tuscaloosa, without refer- 

 ence of their being from another district. 



In Mr. Anthony's paper (Proc. Acad. Nat. Sci. Feb., 1860), I recognize several of 

 my old species. His Oyrotoma demissa I believe to be my Schizostoma constricta. 

 His Q. quadrata to be my S. incisa. 



Schizostoma Showalterii. PI. 35, fig. 49. 



Testa transverse costata, subcylindracea, crassa, castanea, minute striata ; spira elevata ; suturis impres- 

 sis; anfractibus subplanulatis ; fissura submagna, profunda; apertura subparva, elliptica, intus vit- 

 tata ; columella subcrassa ; labro paulisper crenulato. 



Shell transversely ribbed, subcylindrical, thick, chestnut color, minutely striate ; 

 spire elevated ; sutures impressed ; whorls flattened ; fissure rather large and deep ; 

 aperture rather small, elliptical, banded within ; columella thick ; outer lip slightly 

 crenulate. 



Operculum ovate, with the polar point near the inner lower edge. 



Schizostoma Showalterii, Proc. Acad. Nat. Sci., 1860, p. 93. 



Hab. — Coosa River, at Uniontown, Alabama. E. R. Showalter, M. D. 



My cabinet and cabinet of Dr. Showalterr 

 Diam. -46, Length -98 inch. 



Remarks. — Two specimens of this fine species of Schizostoma were sent to me last 

 year by Dr. Showalter, after whom I have great pleasure in naming it. His zeal and 

 industry has done much to discover very many new species of molluscs which inhabit 

 that part of Alabama in which he resides. This species differs much from any I have 



