50 CATALOG OF FOSSIL FISHES IN THE MUSEUM 



E 2383 A left antero-superognathal, lacking the inner flange; in 

 matrix, shown in outer view. Height, 76 mm. 



E 1985 An imperfect right antero-dorsolateral. The plate is of fair 

 size and shows the articulating process. The upper sur- 

 face is much obscured by a very thin deposit of matrix, but 

 the ornamental denticles may be seen in places, and the 

 lateral line is preserved (though it is much obscured), as 

 well as the excavation on the right for overlap by the 

 lateral plate. Posteriorly the element thins out to a 

 paper edge apparently not far from the natural margin. 



Length, antero-posteriorly, without process, 13 cm.; 

 width (allowing for missing left margin), about 20. 



It seems to us probable, because of its size and the 

 character of the ornamental denticles, that this plate be- 

 longs to D. newberryi. 



E 1986 Postero-median ventral. This specimen is smaller than that 

 of the Portage specimen (E 2032) illustrated in figure 17; 

 and it was clearly not fused with the antero-ventro- 

 lateral. (PI. 28, fig. 3.) 



Dinichthys pustulosus Eastman 

 (PI. 12; pi. 13, figs. I, 2) 



This species is represented in the collection by material from three 

 different horizons and localities : 



I. A number of plates from the typical formation and locaHty, the 

 Hamilton limestone of Wisconsin. Some of them display the char- 

 acteristic ornamentation consisting of small tubercles stellate at theii 

 bases. Two of the specimens are plates not previously known in this 

 species — the antero-superognathal and the antero-ventromedian. 



The antero-superognathal (PL 12, fig. i), may be regarded as a 

 rather primitive, unspecialized example of this element. The inner 

 face (the one bearing the secondary tooth) is broad, the tooth propel 

 is small, and the articulating process short. The other two elements 

 of the jaw, the mandible and the postero-superognathal, have already 

 been described, so that the entire dentition of D. pustulosus is now 

 known. 



The antero-ventromedian (PL 12, fig. 2) is of the form usual for 

 this element. Its outer face is covered with ornamental denticles. It 



