32 PALEONTOLOGY OP OHIO. 



inents of plates have been collected, some of which may have belonged to 

 this region of the body. 



Clavicles f — Reference has been made, on a preceding page, to the dis- 

 covery by Mr. Jay Terrell of most of the bones of one large individual of 

 Dinichthys Terrelli, lying together, but not in apposition. The more im- 

 portant of them ai-e fignred on Charts Y. and YI., but with these are found 

 several bones which have not yet been described. Two of them, form- 

 ing a pair, are apparently Scapulo-coracoids (Clavicles, Parker). These are 

 nearly two feet in length, and very massive. They are considerably 

 curved in outline, about six inches broad in the widest part, toward the 

 other extremity narrow and forked. The external surface is granulated 

 like the bones of the head. 



There are also two other plates of which the places are not yet deter- 

 mined. Of these, one is eighteen inches in length, seven inches wide in 

 ■ the middle, where it is broadest, and narrowing to the extremities, which 

 are subacute. One of the sides is nearly straight, the other arched. 



Only the centi-al portion of this bone was exposed, as all the mar- 

 gins, except the straight one, are deeply impressed by the associated plates 

 which broadly overlapped it. Whether this formed part of the defenses 

 of the body, or protected the side of the head cannot yet be certainly 

 told. Another plate found with this, is elliptical in outline, fifteen inches 

 long (and incomplete at both ends) by ten inches wide. It is thin, flat, 

 and without ornamentation. We may infer, from its symmetry, that it 

 was placed on the median line. It is probable, also, that it was located 

 on the under side of the body, but whether before or behind the ventral 

 shield, remains to be determined. 



With one of the heads of D. Terrelli, found at Sheffield, were two 

 bones, forming a pair, which apparently correspond to those figured by 

 Hugh Miller and Prof. Pander in their illustrations of Asterolepis, and 

 called by the latter, ossa anteriora lateralia capitis. They are rudely 

 triangular in outline, the broader side very thick. They were probably 

 set on either side of the head near the muzzle, and formed the supports 

 of the maxillaries. 



Gekus COCCOSTEUS, Agass. 



CoCCOSTEtrS OCCIDENTALIS (n. Sp.). 

 Plate LEI., Pigs. 2, 2 a. 



Posterior dorsal plate somewhat urn-shaped in outline, four inches in 

 length, one and a half inches in breadth, broadly emarginate above and 

 terminating posteriorly in a long, acute, smooth, styliform point. The 



