BUFFALO SOCIETY OF NATURAL SCIENCES 109 



Owing to the refractory character of the Conodont bed limestone, 

 it is very difficult to extricate the tritors from the matrix; the speci- 

 mens are usually broken and in most instances the thin side walls 

 are lost. These specimens agree well with those from the Hamilton 

 of Milwaukee, from which they are specifically indistinguishable. 



E 1913 Three small upper dental plates in splendid preservation 

 (PI. 36, figs. I, 2 ; PL 37, fig. 9). They show the low beak, 

 the entire tritor and the bevelled cutting margin. They 

 are relatively shorter and broader than the upper dental 

 plates of P. compressus, and the region back of the 

 tritor falls away uniformly all around; i.e., the inner and 

 outer faces do not meet in a sharp edge behind the tritor 

 as in P. compressus. The smallest of the three elements 

 is 22 mm. in length (including i mm. allowed for missing 

 posterior extremity). The next larger element is 37 mm. 

 in length; height of beak (its lower margin is completely 

 preserved), 10 mm. (including i mm. allowed for missing 

 tip); max. width of tritor, 4.5 mm. The tritor shows 

 clearly the rows of punctse. The largest element is 40 

 mm. in length; height of beak, 9; max. width of tritor 

 4. The tritor is much worn and the rows of punctae 

 while present are scarcely seen. 



E 2409 Two imperfect tritors of dental plates much larger than the 

 preceding. They clearly belong to P. calceolus as shown 

 by their width, which is much greater than in P. com- 

 pressus, and, in one of them at least, the absence of the 

 ridge behind the tritor. The larger of the two specimens 

 shows the rows of punctse, although they are obliterated 

 in places through wear. In the other specimen— the 

 posterior half of a tritor — the punctae have been afinost 

 entirely obliterated. 



E 2431 A left upper dental plate shown, natural size, in Plate 36, 

 figure 10. The beak is rounded off, and just behind it is 

 a bevelled area produced by the play against it of the 

 left lower beak. 



