DEVONIAN FISHES OF IOWA 201 



of Warren county, Pennsylvania, but the present writer is un- 

 acquainted with any evidence which will enable one to state 

 positively that the species is identical with any of the Ohio Upper 

 Devonian forms. It is to be hoped that more characteristic 

 remains from the eastern region may yet be brought to light. 



Formation and locality. Cleveland shale (Upper Devonian) ; 

 Ohio. Presumably also in the Chemung of Pennsylvania. 



Genus PROTITANICHTHYS Eastman. 



Primitive Coccosteans of small size, displaying synthetic 

 characters of later forms. Arrangement of cranial roofing plates 

 in general resembling that of Coccosteus, the centrals meeting 

 in a sinuous longitudinal suture and not in contact with the 

 pineal; the latter is subelliptical in outline, its major axis di- 

 rected transversely, and pierced by a relatively large pineal 

 foramen ; rostral plate also very broad. External surface finely 

 tuberculated ; lateral margin of headshield apparently not much 

 widened posteriorly; sensory canals distinct; dentition and ab- 

 dominal armoring unknown. 



ProtitanicMhys fossatus Eastman. 

 (Text-fig. 30) 



1907. Protitawichthys fossatus C. R. Eastman, Mem. N. Y. State Mus. 10, p. 

 144, pi. 10, fig. 2, text-fig. 30. 



The unique headshield which has been described under this 

 name is of interest in two respects : first, on account of its geo- 

 logical antiquity, and secondly, because it displays synthetic 

 characters. In the majority of its features, a close approxi- 

 mation is to be observed to typical Coccosteans, especially the 

 more primitive species of Dinichthys, such as D. halmodeus for 

 example. Of relatively small size, its superficial ornament con- 

 sists of fine, closely crowded tubercles with stellate bases. The 

 undulating suture line between the pair of central plates is a 

 distinctly Coccosteus-like feature, and so, too, is the exclusion 

 of the pineal from contact with this pair. The form of the head- 

 shield appears to have been long and narrow, without much 

 lateral expansion across its posterior portion. One striking 



