BUFFALO SOCIETY OF NATURAL SCIENCES 123 



E 2452 Beak of a left lower dental plate. 



E 2447 Tritoral region of a dental plate, much worn by use. 



Palaeomylus sp. [Juvenile?] 

 (PI. 40, figs. 4, 5) 



E 2448 A small dental plate with the gre!aj:er portion of its outer face 

 embedded in matrix. Total length 29 mm.; height at 

 beak 13. The beak is clear of matrix on all sides and 

 well preserved. This and the functional margin are con- 

 siderably worn. A striking feature about the element is 

 that the outer and the symphyseal faces are at right 

 angles to each other, forming a sharp ridge along the 

 front of the beak. 



This elemeait is probably a juvehile dental plate of 

 Palceomylus. The reasons for referring it to this ge,nus 

 are: (i) its general form and the presence of two small 

 tritors back of the beak; (2) the fact thafthe tritoral 

 region shows the ends of tritoral canals forming the char- 

 acteristic ptyctodont rugose wiiearing surface. 



Cono,dont bed (Genesee) ; Eighteen Mile Creek, near 

 North Evans, Erie County, N. Y. Collected by W.L. 

 Bryant. * 



E 2449 Impression of the oral margin of a small palaeomylid dental 

 plate, together with a cast made from it. (PI. 40, fig. 5.) 

 It shows the beak and the two tritors very perfectly. 



Pyrite layer of the TuUy horizon; Cazenovia Creek, 

 near Springbrook, N. Y. Collected by W. L. Bryant. 



Deinodus bennetti. n. gen., n. sp. 



(Pis. 42, 43) 



E 1856 Type. — Dental plate in limestone, shown in outer view; in 

 counterpart. The specimen is slightly defective pos- 

 teriorly, and also at the upper end of the symphysis. 



Formation and Locality. — Onondaga Limestone (Mid. Devonic) ; 

 Cement Quarry, Buffalo, N. Y. Collected by W. L. Bryant. 



Dental plate subrectangular, its depth contained about twice in the 

 length. Functional margin a grinding edge worn on outer face, 



