62 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 68- 



Vag» 



Fig. 21. Panderodella maxillaris, new species 53 



The type of the species, a left plate, showing the thick ante- 

 rior end. 



22. Distacodus rectus, new species Q 



View of type, a nearly straight elongate tooth flaring at the 

 base. 



23. Polygnathun, species 43 



Side view of plate. 

 24,25. Polygnathus pennatulus, new species (see also pi. 7, fig. 8) — 45 

 Side views of right and left plates. 



2(1, 27. Polygnathus, species 43 



Side view of plates of two undetermined species. 



28. Ligonodina simplex, new species 15 



The type specimen showing the bar without denticles and 

 the recurved cusp. 



Plate 10 



All the illustrations on this plate are magnified 15 diameters. The speci- 

 mens are from the Hardin sandstone basal member of the Mississippian-Chat- 

 tanooga black shale at Mount Pleasant, Tenn. 



Page 



Fig. 1, 2. Lonchodina discreta, new species 36 



A young example (1) and a larger tooth (2) showing the 

 curvature of base and widely separated denticles. 



3. Euprioniodina peculiaris, new species 30 



View of this large species. 



4. Lonchodina rectangulata, new species 37 



The strongly curved tooth with small median denticles. 



5. Palmatodella delicatula, new species 41 



Portion of an imperfect specimen. 



6. Bryantodus minutus, new species 2T 



Tooth of this minute species with large median cusp. 



7. Bryantodus tenuis, new species 2G 



View of the very slender tooth with closely arranged 

 denticles. 



8. Bryantodus incertus, new species 27 



Tooth of this large species. 



9. Bryantodus nelsoni, new species 2S 



Tooth showing resemblance to Hindeodella. 



10. Bryantodus gracilis, new species 27 



View of the type illustrating similarity to B. subradiafus. 



11. Bryantodus pergracilis, new species 27 



Tooth of this slender species with rather straight base. 



12,13. Bryantodus subradiatus, new species 2G 



Right and left teeth. 



14. Bryantodus crassus, new species 27 



The type specimen, a broken tooth. 



15, 16. Bryantodus subbrevis, new species 28 



Opposite teeth exhibiting the characteristic short form 

 and semiovate outline. 



17. Bryantodus insolens, new species 25 



Specimen showing the prominent median cusp and un- 

 equal arrangement of denticles. 



