BEEDE : NEW FOSSILS. 151 



more closely than any other species. It is distinguished from P. %ub- 

 ouneatus Meek by its short, thick form and larger size. This species 

 is the more abundant of the two in the Permian rocks of the Big Blue 

 series, while P. subcuneata only has been identified from the Cimar- 

 ron series. 



Allorisma kansasensis, n. sp. Plate V, figs. 6, Qd. 



Shell small, rather gibbous, transversely subovate. Beaks promi- 

 nent, incurved, approximate, located about one-third the length of the 

 shell from the anterior end. Anterior outline descending obliquely 

 from the beaks nearly to the ventral margin, where it turns rather 

 abruptly backward along the nearly straight basal edge to the pos- 

 terior extremity, where it rounds off regularly upward and then for- 

 ward to meet the hinge. The hinge is apparently straight and more 

 than half as long as the shell. The umbonal ridge is prominent, 

 rounded, ill-defined, fading away at the extremity of the shell. Above 

 this ridge is a depression which, with the smooth, elevated hinge, 

 would cause a strong keel on the shell back of the beaks. The con- 

 centric ribs are prominent, fading out at the upper part of the um- 

 bonal ridge and near the anterior border. These ribs are quite as 

 prominent on the casts as on the shell itself. On the central and 

 postero-central regions are the characteristic distant, radiating rows 

 of fine, closely set granules. The shell is less convex below and back 

 of the beak than on either side of this region, though it is not con- 

 cave. The length varies from 1.7 to 1.4 the height. 



Position and locality : Upper Coal Measures, Howard limestone, 

 Topeka, Kan. 



This species is very closely related to A. curta Swallow, but differs 

 from it in having a straighter hinge and a more remote beak. It is 

 from a lower horizon. In the latter respect it differs from McChes- 

 ney's species also. 



Paleontological Laboratory, Indiana University, 

 May 22, 1902. 



