464 PKOCEEDINGS OF THE ACADEMY OF 



than wide; spire much depressed, or nearly flat; volutions four to four and 

 a-half, convex, increasing rapidly in size, last one large, or forming about 

 eight-ninths of the entire length, prominent and narrowly rounded above, 

 contracted and extended below; suture well defined; aperture large, longer 

 than wide, obovate, the inner side being nearly straight; columella not 

 perforate; surface (of an exfoliated specimen) retaining traces of rather strong 

 revolving lines. 



Length 1-21 inches; breadth 1-17 inches; length of aperture 1-05 inches; 

 breadth of do. 0-63 inch; apical angle regular, divergence 132. 



It is only provisionally we have placed this species in the genus Plaiyostoma; 

 the only specimen yet obtained being merely a cast retaining portions of the 

 shell, but not giving a clear idea of its generic characters. It differs from the typi- 

 cal species of that genus in having revolving lines, and will probably be found to 

 present other differences. When better specimens can be examined, we suspect 

 it will prove to belong to an undescribed genus, though we have not the means 

 of settling the question at present. If a new genus is established for its reception, 

 a shell figured by Murchison, De Verneuil and Keyserling (Geol. Russia, pi. 23, 

 fig. 14), as an undetermined species of lanthina, (= Scalites Verneuilii, of 

 D'Orbigny), should probably be placed in the same group. 



Locality and position. Grayville, Illinois. Coal Measures. 



Genus EUNEMA,. Salter. 



Eunema? Salteri. Shell elongate conical, turreted, acute at the apex. Volu- 

 tions thirteen, slightly convex, increasing very gradually in size, ornamented 

 by two small revolving carina? a little below the suture, the lower one of which 

 is larger than the other; last whorl having a third angle near the middle, 

 which passes around just above the suture on the other volutions ; below 

 this third angle there is on the under side of the last turn a fourth nearly 

 obsolete revolving prominence. Suture linear. Apertuce ovate, a little oblique. 

 Columella arcuate, not perforate. Lines of growth fine, rather obscure, and 

 passing straight across the whorls. 



Length 0-50 inch; breadth 0-17 inch. Length of aperture 0-17 inch; breadth 

 0-10 inch. Apical angle convex, divergence 20. 



This beautiful little shell differs from the typical species of the genus in 

 which we have provisionally placed it, in having the lines of growth straight 

 instead of sinuous. This character, and the revolving carinas, would also 

 separate it from Loxonema, to which we were at first inclined to refer it. On 

 a hasty examination it might be referred to the genus Murckisonia, some species 

 of which it nearly resembles in its general appearance ; a careful examination, 

 however, has satisfied us that its lines of growth do not make the slightest 

 curve, so as to indicate the existence of a sinus in any part of the lip. We 

 suspect it may belong to an undescribed genus; though, if it were from a more 

 modern formation, we should scarcely hesitate to place it in the genus Turritella. 



Named in honor of Mr. J. W. Salter, the distinguished Palaeontologist of the 

 British Geological Survey. 



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



Genus LOXONEMA, Phillips. 



We doubt the propriety of referring such forms as are here described, to the 

 recent genus Turbonilla, (Chemnitzia, D'Orbigny,) since they are generally 

 not only much larger shells, but differ in not having, so far as we have been 

 able to see, the apex of the spire reversed, as in the species upon which the 

 genus Turbonilla was founded. We therefore agree with those who prefer to 

 retain Phillips' name, Loxonema, for these older fossil species. 



Loxonema scitula. Shell small, elongate, conical ; spire elevated and regu- 

 larly tapering ; volutions eight to eight and a half, very slightly convex, in- 

 creasing gradually in size, last one rounded and not produced below ; suture 



[Oct. 



