DEVONIC FISHES OF THE NEW YORK FORMATIONS 1 43 



turns out to have been a large dorsomedian of DInichthys. The error to 

 which we have called attention is corrected in the new restoration given 

 herewith. 



We come now to speak of the clavicular, a plate which has been 

 curiously misinterpreted both in this genus and in Dinichthys. The frag- 

 mentary example figured by Newberry in plate 3, figure 3 of his MonograpJi 

 on Palaeozoic Fishes under the name of " coracoid (?)," gives no adequate 

 conception of what the plate was like. We accordingly present an outline 

 drawing and section [text fig. 28] of a nearly perfect clavicular of T. c 1 a r k i, 

 the original of which belongs to the American Museum of Natural History ; 

 and this element is also shown in its natural position, overlapping the 

 antero-dorsolaterals, in the restoration of T. a g a s s i z i given in text figure 

 29. It will be seen from these figures that the external or distal portion of 

 the clavicular is very different from the corresponding portion in Dinichthys, 

 being developed as a stout, slightly curved arm, semicylindrical in cross- 

 section, and not dividing into two branches, nor provided with the peculiar 

 "knuckle joint" described by Claypole in a large specimen of Dinichthys.' 

 The total length of the figured example, measured in a straight line, is 

 65 cm, and it is evident that the rodlike projection must have extended 

 almost, if not entirely free from the body armor on either side. What 

 function it subserved is difficult to imagine, but as likely a conjecture as 

 any is that it furnished a support for the branchial apparatus and attach- 

 ment for the tissues connected with the lower jaw. It is impossible to 

 suppose that plates of such thickness as the clavicular — in the distal 

 process it amounts to upwards of 5 cm — could have been flattened out 

 horizontally by mechanical agencies during fossilization ;' hence, as this bone 

 continues the plane of the head shield and body armor, we are compelled 

 to assign to Titanichthys a depressed form of body, having in the type 

 species the truly enormous expanse from side to side of over 1.5 meters. 



Nothing is known of the ventral armor of Titanichthys, unless we are 

 permitted to assign to this genus certain large, thin plates of lanceolate 



' Ohio Geol. Sur. Rep't. 1893, 7: 610, pi. 38, fig. i; pi. 39, fig. i. 



