380 Miscellanies. 



found in this vicinity this spring, have discovered that it cannot be 

 confounded with it. Among those who thus doubted at first, and after- 

 wards became convinced, I may mention Dr. J. A, Warder lof' this 

 place, who, on a recent visit to Springfield, Ohio, found among some 

 fossils belonging to his sister, a specimen of what he deems another 

 species belonging to the same genus with the present. On consulta- 

 tion, we have concluded to form a new genus, to be called Cerato- 

 A cephala, [horned head.) 



s/ (3.) AsAPHTTs POLYPLEURus. Green.* 



Cly-peo ? costis abdominis duplicihus ; cauda rotunda ; corpore 

 coniyexo. 



This Asaph, at first sight, seems to differ especially from all the 

 other American species hitherto noticed, in the number and thinness 

 of the ribs, or costal arches of the abdominal lobes. When carefully 

 examined, however, it becomes obvious that the apparent number of 

 the ribs is produced by a straight longitudinal furrow on the upper 

 surface, which divides each rib into two nearly equal portions, thus 

 seemingly doubling their number. These furrows or grooves do not 

 terminate in the costal arches, but extend, in several instances at least, 

 beyond, into the membranaceous expansion by which they are sur- 

 rounded. The ribs therefore do not end in free angular points, as 

 those of the A. Wetherilli, the A. Limulurus, and some others. The 

 membranaceous expansion forms a narrow semicircular border round 

 the lateral and caudal edges of the body. The middle lobe of the 

 back is very prominent. The animal is decapitated, and the fragment 

 described measures in length and breadth three fourths of an inch. 



The above trilobite occurs in a coarse grained greyish limestone, 

 which contains other fossils. It was found by that distinguished geol- 

 ogist, Richard C. Taylor, Esq., in the state of Missouri, on the bank 

 of the Mississippi, near the mouth of the Des Moins river. It is to be 

 regretted that our fossil is so much mutilated and worn ; but enough 

 yet remains to identify from it the species, when perfect specimens 

 shall be discovered. The prominence of the middle lobe of the abdo- 

 men indicates that it may ultimately be referred to some other genus 

 than the Asaph. 



(4.) Additional notices of Trilohites. 



From Mr. J. Walter, of Louisville, Ky., we have received a draw- 

 ing of a trilobite seven and a quarter inches long, by four inches broad. 



* Communicated for this Journal, by Jacob Green, M. D. Professor of Chemis- 

 try in the Jefterson Medical College, Philadelphia. 



