NATURAL SCIENCES OF PHILADELPHIA. 15 



A careful examination of the typical specimen (now before us) of Edrm ndiat 

 radiata, of the Iowa Report, cited above, has clearly satisfied us thai il has 

 the ligament on the short side, and certainly belongs to the genus we have 

 here described, and we can scarcely doubt that it is really the same species as 

 our type. As none of our numerous specimens, however, show tbe radiating 

 markings so distinctly as that described by Prof. Hall, we have concluded t<> 

 view them as belonging to a smooth variety, which we propose to designate 

 under the name Levis. 



Locality and position. Near base of Coal-measures, Seaville county, Illinois. 

 Prof. Hall's specimen came from the upper beds of the Coal-measures at 

 Grayville, Illinois. 



GASTEROPODA. 



Dentaliuji annclostriatum, M. and \Y. 



Shell very small, rather distinctly tapering and slightly arched ; aperture 

 and section circular ; surface ornamented by regular, distinct, annular costae, 

 which pass around a little obliquely and are separated by rounded furrows of 

 the same breadth as the costa3 themselves. 



Length of a specimen incomplete at both ends, 0-28 inch ; diam. at the 

 larger end, 0-06 inch ; do. at the smaller end, 0-0-1 inch. 



Of this delicate little shell we have seen but a single specimen, which is 

 imperfect at both ends. At a first glance, it might be mistaken for another 

 more common species, of near the same size, occurring at the same locality, 

 and which we are inclined to think is the D. Meekianum of Geinitz. On exam- 

 ining it under a magnifier, however, it can be at once distinguished by its 

 comparatively strong, regular costaj, instead of mere microscopic lines of 

 growth. 



It is with some doubt that we have referred this little shell to the genus 

 Dentalium, because its small size and comparatively strong, regular costae give 

 it much the appearance of the non-spiral part of the shell of a Citcum. It is 

 more arched, however, and more tapering than we generally see in the body 

 part of shells of that genus, which are likewise, we believe, unknown in any 

 of the Palaeozoic rocks. 



Locality and position. Shales over the Danville Coal, holding a position 

 about the horizon of the fifth Coal of the Illinois ; or, near the upper part of 

 the lower Coal-measures. 



Straparollds (Ecomphalus) pernodosus, M. and W. 



Shell attaining a rather large size, subdiscoidal, or with the spire nearly on 

 a plane with the upper outer edge of the body volution; umbilicus broad, 

 moderately deep, and showing all the inner turns ; volutions about five and a 

 half flattened-convex, and a little oblique on the broad periphery, but dis- 

 tinctly carinated near the outer side above (the carina being rugose), while a 

 little outside of the middle below, they are prominent and ornamented by a 

 row of moderately distinct nodes, of which about sixteen may be counted on 

 the last turn ; those on the last half of the outer volution becoming nearly 

 or quite obsolete toward the aperture. Upper side of each whorl flattened 

 and sloping distinctly inward from the carina to the suture ; lower side o 

 same sloping rapidly inward and slightly concave just within the prominent 

 nodose ridge, and then rounding rather abruptly into the umbilicus. Surface 

 marked by distinct lines, and at some places ridges, of growth ; on the upper 

 side of the whorls these lines pass obliquely outward and forward from the 

 suture to the carina, thence obliquely backward in crossing the periphery, 

 while in crossing the under side they curve a little backward 



Greatest breadth of a specimen not quite complete at the aperture, . 50 

 inches; height at the aperture, about 0-84 inch. 

 1870.] 



