DEVONIC FISHES OF THE NEW YORK FORMATIONS I4I 



of but slight movement between the parts. In the type species at least, the 

 antero- and postero-dorsolateral plates are completely fused, and are over- 

 lapped to a relatively greater extent by the dorsomedian than in Dinichthys. 

 Particular attention is claimed by the last named plate, for the reason that 

 its relations have not been clearly understood. It would appear that our 

 only knowledge of the dorsomedian in Titanichthys is confined to a single 

 specimen, identified by Newberry as belonging to T. clarki, but wrongly 

 referred by him to the "underside of the body or head."' A figure of it is 



:. 27 Dorsomedian pi: 

 . 28 Clavicular of T 



given, with the posterior margin uppermost, in plate 3, figure i of New- 

 berry' s monograph, and its outlines are reproduced in the accompany- 

 ing text figure 27. The original is now preserved in the Americar 

 Museum of Natural History in New York, after having remained for some 

 time inaccessible in the collections of Columbia University. Newberry's 

 failure to recognize this plate as a dorsomedian is probably to be explained 

 by the fact that its visceral aspect is embedded in the matrix, thus conceal- 

 ing the characteristic longitudinal keel. That the latter was present, how- 



' U. S. Geol. Sur. Monogr. 1889. 16: 135. 



