Eastman. — Mylostoma. 



PLATE 2. 



Upper Dentition of Mijlostomids. 



Fig. 10. Left posterior palato-pterygoid dental plate of Mijlostoma variabile Newb. 



Original preserved in American Museum of Natural History (Cat. 



No. 44 G). 

 Fw. n. Same as preceding. Original preserved in the Museum of Comparative 



Zoology (Cat. No. 1438). 

 Fig. 12. Left anterior palato-pterygoid dental plate of Mylostoma variabile Newb. 



Original preserved in American JNIuseum of Natural History (Cat. No. 



3290). 

 Figs. 13, 14. Vomerine teeth of Dinomi/lostoma beecheri Eastman, seen from the 



posterior aspect, and showing gently concave surface for co-adaptation 



with the anterior pair of palato-pterygoid elements. Originals in 



Peabody Museum, Yale University. 

 Fig. 15. Right posterior palato-pterygoid dental plate of Mylostoma variabile 



Newb. turned with the posterior margin uppermost, or in opposite 



position from Figs. 8, 9, 10 and 17. Type specimen figured in Plate 



15, Fig. 5, of Newberry's Monograph, 1889. Original preserved in the 



Museum of Comparative Zoology (Cat. No. 1436). 

 Figs. 16, 17. Posterior pair of palato-pterygoid dental plates of Dinomtjlostoma 



beecheri Eastman, to be compared with Figs. 8 and 9 of Plate 1. 

 Fig. 18. Vomerine tooth of a small undetermined Coccostean, possibly of Dinich- 



thys, shown for purpose of comparison with the vomerine teeth of 



Mylostoma. 



All specimens are shown of the natural size, and with the exception 



of Figs. 13,14, 10, and 17 are from the Cleveland shale (Upper Devonian) 



of Sheffield, Ohio. 



