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bulletin: museum of comparative zoology. 



element. We will conclude our description of the new form by pre- 

 senting measurements of the more important elements as follows : 



The vomerine teeth have a length along their narrow longitudinal 

 margin of 3 cm. Their width across the posterior face in a transverse 

 direction is 3.5 cm., and obliquely across the external face it is 4 cm. 

 The posterior palato-pterygoid dental plates have major and minor axes of 



Fig. H. — Diagram showing contour of oral margin of mandibular and posterior palato- 

 pterygoid dental plates of Dinomylo stoma beecheri Eastman, in front of which are shown 

 the upturned vomerine pair, all drawn to the same scale, and the members of each pair 

 placed in natural position with respect to each other. X §. 



6.8 and 5 cm. respectively, and a thickness of about 2 cm. except in the 

 central portion where the dome-shaped tubercle increases it to a total of 

 2.5 cm. The extreme length of the mandible falls a trifle short of 20 cm., 

 that of the functional margin is about 8 cm., and the maximum width of 

 the latter is 2.3 cm. The dorso-median plate, indistinguishable in form 

 from that of Dinichthys intermedins, and with well developed posterior 

 process, is estimated to have had a total width of 18 cm. It is unfortu- 



