Plate VII. 



EXAMPLES OF CTENODIPTERIXE DENTITION, MOST- 

 LY FROM THE IOWA UPPER DEVONIAN. 



All figures are of the natural size. 



Figs. 1-4. Dipterus nelsoni Newberry. Chemung; Warren. 

 Pennsylvania. In Fig. 1 is shown a right upper dental plate 

 of the so-called "D. flabelliformis" type, and in Figs. 2-4 the 

 corresponding mandibular dental plates of both sides of the 

 mouth. The original of Fig. 2 is one of Newberry's cotypes 

 of this species, and is now preserved in the Peabody Museum at 

 Yale University. The others are the property of the Museum 

 of Comparative Zoology at Cambridge. The original of Fig. 

 3 is also shown in Plate II, Fig. 11, 11a. Page 223 



Figs. 5-9. Dipterus mordax Eastman. State Quarry beds 

 (Upper Devonian) ; Johnson county, Iowa. Small sized ex- 

 amples of the inferior dental plates, to be compared with those 

 shown in Plate II, Figs. 4, 5. Page 220 



Figs. 10-15. Dipterus pectinatus, sp. now State Quarry beds 

 (Upper Devonian) ; Johnson county, Iowa. Lower dental plates 

 represented in Figs. 10, 13, 14; upper in Figs. 11, 12, 15. The 

 original of Fig. 13 is also shown in Plate II, Fig. 2. Page. .222 



Figs. 16-25. Dipterus digitatus, sp. nov. State Quarry beds 

 (Upper Devonian) ; Johnson county, Iowa. Lower dental plates 

 represented in Figs. 16-19, 25; upper in Figs. 20-24. The orig- 

 inal of Fig. 20 is also shown in Plate II, Fig. 6. Page 221 



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