Description of a new Trtlohite. 167 



Art. XVII. — Description of a new Trilohiie ; by Jacob Green, 

 M. D., Professor of Chemistry in Jefferson Medical College, 

 Philadelphia. 



Calymene Phlyctainodes.* — Green. 



Clyjpeo semilunari, lohis inflatis valde punctidatis, antice roiun- 

 datoco ; cauda 1 



I HAVE been for a long time expecting to find among the trilo- 

 bites of North America, a species analogous to the C. variolaris, 

 which is sometimes met with among the fossils at Dudley in Eng- 

 land. Its association with the C. BlumenhacMi at that locality, and 

 the occurrence of that species in such numbers in the transition 

 limestone so extensively spread over the United States, induced the 

 belief that it would sooner or later be discovered in our rocks. 



Dr. William Blanding of this city, has recently received from 

 Springfield (Ohio,) a number of very perfect specimens of the C. 

 Blumenbachii and other fossils. In this rich parcel I had the pleas- 

 ure of discovering a fine fragment of the buckler, of a species not 

 very unlike the C variolaris of Professor Brongniart, — Plate I, 

 fig. 3, A, — the original of which came from Dudley, and is said to 

 be now in the collection of Mr. Johnson, of Bristol, (Eng.) 



Nearly the whole of the buckler of our species is perfect, in the 

 specimen I have examined. The middle lobe is large, and very 

 prominent : there are no folds or tubercles upon it, as in the C 

 Blumenbachii, or the C. macrophthahna, but the whole of its sur- 

 face, as well as that of the cheeks, is covered with distinct, rounded 

 grains, or warty pustules. The C. variolaris is also furnished with 

 a similar structure, but Prof. Brongniart states that the pustulations 

 in that species, are all pierced at their summit with a small hole, 

 like the tubercles on the genus Cidaris among the Echini : this is 

 not the case in our species, the tubercles being all imperforate; they 

 resemble exactly in this respect those on the shell of the Echinus 

 mammillaris of Lamarck. The whole contour of the cheeks or side 

 lobes of the buckler, cannot be made out from our fragment ; they 

 no doubt, however, form spherical triangles ; each cheek is divided 

 by a deep groove into two lobes ; the portion of the lobe nearest 



* Phlyctainodes — from the Greek, for pustulated. 



