NATURAL SCIENCES OF- PHILADELPHIA. 465 



moderately well defined ; aperture obliquely ovate, acutely angular above. 

 Surface ornamented by distinct, regularly disposed, straight vertical folds or 

 costae, about fourteen or fifteen of which occupy each turn ; folds equalling 

 the depressions between, and on the last turn becoming suddenly obsolete 

 below the middle ; no lines of growth visible. 



Length 0-23 inch ; breadth, 0-10 inch ; length of aperture, 0-07 inch ; breadth 

 of do., 0.04 inch. Apical angle regular, divergence 25. 



Locality and position. Springfield, Illinois. Upper Coal Measures. 



Loxonema rugosa. Shell small, elongate, conical ; volutions seven and a 

 half to eight, very slightly convex, increasing gradually in size, last one abruptly 

 rounded in the middle, not extended below ; suture rather slightly impressed ; 

 aperture ovate. Surface of each whorl ornamented by about eighteen to nine- 

 teen straight, distinct, vertical folds or costae, which equal the depressions 

 between, and are disposed so as to range in regular lines from the last whorl 

 to the summit of the spire ; those on the body whorl becoming abruptly obso- 

 lete below the middle. No lines of growth visible. 



Length, 044 inch ; breadth 0-18 inch ; length of aperture 0-12 inch ; breadth 

 of do., 0-08 inch. Apical angle convex above, divergence 25. 



Near the last, but differs in having the spire less attenuate above, and in 

 having more costae to each turn. The costas also differ in being ranged in 

 right lines, all the way up the spire, while those of the adjacent whorls, in the 

 last, alternate. This latter character gives quite a peculiar aspect to this 

 species. 



Locality and position. Same as last. 



Loxonema cerithiformis. Shell rather under medium size, elongate, conical; 

 spire elevated, gradually tapering to an acute point. Volutions, eleven to 

 twelve, convex, and increasing gradually in size ; last one not much enlarged, 

 somewhat prominently rounded below the middle. Suture well defined. 

 Aperture oval, subrhombic, a little longer than wide, apparently provided 

 with a small, rather oblique notch at the base of the columella ; outer lip thin, 

 broadly and deeply sinuous above and prominent below, so as to present a dis- 

 tinct inversely sigmoid outline ; columella arcuate. Surface nearly smooth, but 

 showing under a lens very fine, obscure lines of growth, which curve parallel 

 to the margin of the lip ; just below the suture these lines are gathered into a 

 series of minute, short, regularly arranged wrinkles or crenulations, scarcely 

 visible without the aid of a magnifier. 



Length, 0-70 inch ; breadth, 0-24 inch ; length of aperture, 0-18 inch ; breadth 

 of do., 0-11 inch. Apical angle regular, divergence 24. 



Appears to agree very nearly with Chemnitzia subconstricta of Koninck, in 

 form and surface markings ; but differs, in the form of the aperture, and in 

 having a small notch or sinus, with a slight projection of the lip, at the base 

 of the columella. 



Locality and position. Springfield, Illinois. Upper Coal Measures. 



Loxonema inornata. Shell small, conical subovate ; spire moderately 

 elevated, pointed at the apex ; volutions seven, slightly convex, increasing 

 rather gradually in size, last one somewhat prominently rounded in the 

 middle, but not ventricose ; suture rather shallow ; aperture narrow sub- 

 ovate, acutely angular above, narrow, and provided with a small rounded 

 sinus at the base of the columella below ; columella arcuate ; outer lip thin, 

 and apparently but slightly sigmoid in outline ; surface smooth, or only show- 

 ing very obscure traces of fine lines of growth under a good lens. 



Length, 0-38 inch ; breadth, 0-18 inch ; apical angle convex, divergence 

 about 30. Length of aperture, 0-16 inch ; breadth of do., 0-09 inch. 



Locality and position. Springfield, Illinois. Upper Coal Measures. 



Loxonema nitidula. Shell of medium size, subfusiform ; spire elongated, 

 I860.] 



