NATURAL SCIENCES OF PHILADELPHIA. 467 



Length, 1-12 inch; breadth, 0-68 inch; length of aperture, 0T2 inch; 

 breadth of do., 0-39 inch. Apical angle convex, divergence 83. 

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



Macrocheilus intercalaris. Shell of medium size, rhombic, oval ; spire 

 conical, forming more than one-third of the entire length, pointed at the ex- 

 tremity. Volutions six to seven, compressed convex, increasing rather rapidly 

 in size; last one comparatively large, but not ventricose, widest near the 

 middle, and compressed above. Aperture narrow, subovate, a little oblique, 

 narrowly rounded, and faintly sinuous below, acutely angular above : outer 

 lip thin, slightly prominent along the middle ; columella having a small 

 sinuosity in the middle, below which the lip is thickened, so as to form a 

 moderately distinct oblique fold or obtuse prominence ; inner lip not much 

 thickened above. Surface smooth, but showing obscure traces of very fine 

 lines of growth under a magnifier. 



Length, 1-14 inch; breadth, 0-70 inch. Length of aperture, 0-70 inch; 

 breadth of do., 0-32 inch. Apical angle convex, divergence 74. 



Locality and position. Same as last. 



Macrocheilus pulchellus. Shell of medium size, rhombic, oval, or sub- 

 fusiform ; spire rather elevated, pointed at the apex, composing more than 

 two-fifths the entire length. Whorls seven and a half, distinctly convex, in- 

 Teasing moderately in size, last one not ventricose; suture well defined. 

 Aperture narrow, subovate, acutely angular above, and rather narrowly 

 rounded below ; outer lip sharp, and slightly sigmoid in outline ; columella a 

 little arcuate, or sinuous in the middle ; inner lip moderately thickened, some- 

 what prominent, or showing a slight disposition to form an obtuse fold below. 

 Surface polished, and having faint traces of fine lines of growth, which can 

 only be seen by the aid of a magnifier. 



Length, 1-30 inch ; breadth, 0-79 ince ; length of aperture, 0-75 inch ; breadth 

 of do., 0-34 inch. Apical angle convex, divergence 64. 



Ijocality and position. Same as last. 



New Genus SOLENISCUS.* 



The shell upon which we propose to found this genus, differs from the smooth 

 species usually referred to Loxoncma in having the body whorl contracted and 

 extended below into a distinct straight canal, with a well defined oblique plait 

 or fold rather low on the columella. In the last mentioned character, as well 

 as in its smooth surface, it agrees more nearly with the genus Macrocheilus. 

 but its fusiform outline, narrow aperture and distinct canal, are peculiarities 

 which separate it clearly from that group, as usually understood. In its 

 general appearance it resembles some species of Fasciolaria; but as it has only 

 one, instead of two or three folds on the columella, and is entirely destitute of 

 nodes, costse, or revolving marks, while its outer lip is quite smooth within. 

 there 'is little reason for supposing it to be really nearly related to that genus, 

 which is unknown below the upper Cretaceous. 



It is probable that when the aperture and columella of such species as 

 Macrocheilus lirnnceformis, McCoy, and Macrocheilus fusiformis, Hall, (non M. 

 fusiformis of Morris' Catalogue,) as well as of several of the smooth fusiform 

 species referred by others to Loxonema, are better known, they will be found 

 to possess the characters of this genus. 



Soleniscus typicus. Shell fusiform ; spire elevated, and acutely conical at 

 the apex; volutions seven to seven and a-half, flat or but slightly convex, 

 increasing rather gradually in size, last one comparatively large, slightly ventri- 

 cose in the middle, and contracted into a distinct, straight canal below ; suture 

 moderately well defined ; aperture very narrow, acutely angular above, and 



*aa>Mvi<mo; : a little channel, or gutter. 



I860.] 



