DEVONIC FISHES OF THE NEW YORK FORMATIONS 



155 



Measurements of the more characteristic elements may be given as 

 follows : the vomerine teeth have a length along the inner longitudinal 

 margin of 3 cm; their width across the posterior face is 3.5 cm, and across 

 the external face it is 4 cm. The posterior palato-pterygoid dental plates 

 are of irregularly cruciform outline, with major and minor axes of 6.8 and 

 5 cm respectively. They are about 2 cm in thickness, except in the region 



Fig. 33 Diagram showing contour of oral margin of mandibular and posterior palato-pterygoid dental plates of D i n o m jj- - 

 lostoma beecheri,in front of which are shown the upturned vomerine pair, all drawn to the same scale, and the mem- 

 bers of each pair placed in natural position with respect to each other. x% 



of the centrally placed tubercle, where the total thickness is 2.5 cm. The 

 total length of the mandibles falls a trifle short of 20 cm, that of the func- 

 tional margin about 8 cm, and the maximum width of the latter is 2.3 cm. 

 The dorsomedian plate, closely similar in form to that of Dinichthys 

 intermedius, and with well developed posterior process, is estimated to 

 have had a total width of at least 18 cm; it is unfortunately not preserved 

 for its entire length. The antero-ventrolaterals have approximately the 



