BUFFALO SOCIETY OF NATURAL SCIENCES 43 



Is arched from side to side, which indicates a more natural condition 

 than usual since ventral plates are very thin and generally found 

 flattened out. A thickened process occurs on the anterior edge which 

 is, apparently, a device for interlocking with the antero-median- 

 ventral. Length of plate, 50.8 cm.; anterior border, about 35 cm. 



Both postero-ventrolaterals (PL 7, fig. 3) are preserved. They are 

 exhibited in outer view and show near the anterior margins, the depres- 

 sions into which the distal extremities of the corresponding antero- 

 ventrolaterals fitted. The right postero-ventrolateral lacks the front 

 border, but as far as preserved it measures 38 cm. in length, by 17.5 

 cm. in greatest width. Along the inner margin is an elongated, 

 irregular depression into which the plate of the opposite side fitted, 

 in the manner demonstrated for Dinichthys by A. A. Wright.^^ The 

 surface of the plates is finely tuberculated, and along the inner 

 margin the tubercles have a tendency to a linear arrangement. 



A knife-shaped spiniferous plate similar to that shown in Plate 17, 

 figure 3, was found overlying the cranium in the orbital region. One 

 end is thickened, the other is formed into a sharp blade. 



In addition to the preceding plates there are fragments of two or 

 three others, too imperfect for description. One is a fragment of a 

 suborbital, Ijdng to the right of the cranium and showing a small part 

 of the lateral line that traverses this plate. Another is a fragment of 

 an antero-dorsolateral, showing the articulating process. 



Besides the type specimen there are several plates in the collection 

 which seem referable to this species. They are all from the Conodont 

 bed (Genesee), at Eighteen Mile Creek, near North Evans, N. Y., and 

 were collected by W. L. Bryant. 



E 1936 Functional half of a left mandible represented in outer 

 view in Plate 8, figs, i, la, and in inner view, in text- 

 figure 12. 



We refer this specimen to D. magnificus for the reason 

 that the beak is rather low for a mandible of this size, and 

 the secondary cusp is situated at a considerable distance 

 from it — the two features by which the mandible of this 

 species is especially distinguished. An important char- 

 acter in this specimen is the presence of a row of teeth in 

 the symphyseal region. Only the two lowermost ones 



1' Wright, Albert A.: The ventral armor of Dinichthys. Amer. Geologist, xiv, 313-320, pi. ix^ 



