ART. 21 ORDOVICIAN TRILOBITES ULRICH 33 



places a half dozen or so of pygidia — five of them like the one at 

 Lexington, Va. — and one or two imperfect free cheeks were found 

 with the cranidia. Fewer specimens have been found at other Ap- 

 palachian localities, the most southern being at Pratts Ferry, in 

 central Alabama, in every case in a thin bed of subcrystalline lime- 

 stone at the base of or rather just beneath the Athens shale. 

 Cotypes.— Cat No. 80543, U.S.N.M. 



TELEPHUS IMPUNCTATUS, new species 



Plate 5, Figures 10-15 



This species is based on a number of cranidia that suggest more 

 or less close relations to T. hiptmctatits, T. prattens-is^ and T. telli- 

 coensis without being in any case sufficiently like one or another of the 

 mentioned forms to warrant identification. The general outline of 

 the cranidium is most like that of T. hipunctatus from which it is im- 

 mediately distinguished by the absence of the deep pair of glabellar 

 pits. The glabella is also relatively not so wide posteriorly and 

 its sides less curved, its outline therefore being more conical than 

 in that species. In one of the cranidia referred here (see pi. 5, fig. 

 13), very shallow and small glabellar pits occur that remind one 

 of T. hipunctatus. The proportions of this specimen also differ some- 

 what from the others, the cranidium being relatively longer. 

 Finally, in all of the specimens that preserve the occipital spine it 

 is stronger than in T. hipu/actatus. 



In general aspect these cranidia remind rather more of T. prat- 

 tensis than of T. bipunctatus. In fact the glabella is practically the 

 same as in that species. However, the occipital spine is larger and 

 the fixed cheeks, being wider in front and the outline consequently 

 more sharply recurved, are notably different. In these respects 2^. 

 impunctatus is not much unlike T. telUcoensis. The resemblance in 

 this case is heightened by the strength of the occipital spine. But 

 the cheeks are not quite as wide as in that much younger species nor 

 is the occipital spine as strong or directed so much upward, whereas 

 the glabella is distinctly longer than in the Tellioco species. 



Though the cranidia that I refer to this species in a few instances 

 are not very sharply distinguished from those of the species with 

 which they have been compared the case is quite different with re- 

 spect to the pygidium that was found with them. Though built on 

 much the same plan it is much wider, both as regards the axis and 

 the pleural lobes, and also less convex than are the pygidia found 

 with and assigned to T. bipunctatus, T. hircinus, and T. telUcoensis. 

 As usual the anterior half of the first axial ring carries a pair of 

 small median spines, and the second shows the stump of a single 

 64441—29 3 



