EXPLANATION OF I'LATES 



Pr.ATE 1 



All the illustrations on this plate are ma.icnified 15 diameters and the speci- 

 mens are from the Rhlnestreet shale of the Portage irroup at Shaleton, Erie 



County, N. Y. 



Page 



Fig. 1-3. PolijgnatheUus ti/picaTis. new species 53 



(1) Side view of plate exhibiting curved crest of joined 



denticles and tuberculated concave side. 



(2) Upper side of basal plate. 



(3) View exhibiting convex side of basal expansion. 



4. Polygna thelitis curvatus, new species 54 



The type specimen, the impression of the concave side. 



5. "iGnathodus, species 54 



Specimen ordinarily referred to Gnathodus but which is 

 believed to be a side view of an imperfectly preserved 

 Polygnathus. 



6, 6', 7. J'almatolcpis punctata Hinde. 1S79 51 



Upper surface of two plates, right and left, and under 

 surface of a third. 



8,9. Polygnathus rimulatus, new species 45 



Upper surfaces of two examples of this minute species. 



10-13. Ancyrodella nodosa, new species 48 



Upper and lower surfaces of plates showing slight varia- 

 tions. 



14,15. HindeodeUa alternata, new species 40 



Outer sides of two teeth ; in 14 the minute denticles are 

 little vi.sible, due to orientation of specimen in rock. 



16, 17. Prioniodus curvidens, new species 11 



Two teeth, left and right, illustrating slight forward 

 curvature of denticles. 



18-20. Prioniodus undosus, new species 12 



Three teeth exhibiting the downward curvature of the bar. 



21. Euprioniodina hryanti, new species (see also pi. 3, figs. 



13, 14) 29 



An example resembling a Ligonodina, but the downward 

 projection is provided witli small denticles. 



22. Prioniodus proclinatus, new species 10 



The type specimen showing the large, anteriorly inclined 

 terminal cusp. 



23. Prioniodus inutilis, new species 11 



Tooth with main cusp and denticles rather widely sepa- 

 rated. 



24. Lonchodina subsymmetyica, new species (see also pi. 6, figs. 



5-7; pi. 5, fig. 8) 34 



A broken specimen preserving only the main cusp and part 

 of bar, showing possibility of identification with Pri- 

 oniodus. 



25,26. Prioniodus alatus Hinde, 1879 11 



Two examples of this fine large species. 



< ': 55 



