54 CATALOG OF FOSSIL FISHES IN THE MUSEUM 



excavated for interlocking with the postero-superognathal. More- 

 over, as compared with a juvenile postero-superognathal of D. new- 

 berryi of about the same size, the present element is more slender, 

 has a stronger angle between the tooth and the process portions, in 

 profile view; and the inner face of the process is excavated, instead 

 of being almost fiat. 



Dinichthys sp. (Mandible) 



(PI. 70, fig. 3) 



A Dinichthys mandible of about the size of that of D. curtus was 

 recently collected from the Chemung rocks near the city of Erie, Pa., 

 by Mr. E. J. Armstrong, an engineer and student of invertebrate 

 fossils. He has kindly presented it to the Buffalo Museum. This 

 is the first Dinichthys mandible to be found in the Chemung, and it 

 seems to differ somewhat from other Dinichthys mandibles, so much, 

 in fact, that we believe when an example of it clear of matrix is ob- 

 tained, it wiU probably turn out to be a new species, for which we 

 would propose the name D. Armstrongi be reserved. As the specimen 

 is embedded with its outer face in the rock so that the form of the 

 functional region is not shown, and since the absence of the posterior 

 extremity must leave it a little doubtful as to the exact length of the 

 entire mandible, we deem it best not to name it at this time. The 

 specimen may be described as follows : 



E 2598 A left mandible (PI. 70, fig. 3), in matrix, shown in inner 

 view. The posterior end is lacking. The beak is rather 

 more recurved than in D. curtus or D. intermedius. The 

 second cusp also is rather farther back than in these 

 species. 



cm. 



Length as far as preserved. 22 



Estimated total length 26 



Length of functional portion (measured to its junction 

 with the blade portion) 13 



Numerous fragments of Dinichthys plates have been obtained from 

 the Chemung rocks — portions of crania, and dorsal and ventral plates 

 — but, with one exception, all have been too fragmentary for descrip- 

 tion. There is a large series of such remains in the New York State 

 Museum, at Albany, N. Y., the best of which were at one time sent 



