AKT. 12 CI^SSIFICATION OF CO.NODONTS ULRICH AND BASSLER 13 



In Ligonodhui the lateral denticles are always rounded and clearly 

 separated from each other and there is no tendency to fusion as in 

 PHoniodus. Moreover the bar is always narrower and the main 

 cusp relatively longer, more slender, and, on tlie side bearing the 

 suckerlike cavities, always shows a sharp ridge on the anterior edge 

 of the main cusp causing a concavity just within it, while the op- 

 posite side is regularly rounded. These characters combined give 

 the whole tootli a more delicate appearance. In addition to the 

 new species herein described this new genus includes the follow- 

 ing: L. (Pnoniodus) panderi Hinde, 1879 and L. {Prioniodiis) 

 recedens Bryant 1921, both from the Upper Devonian of western 

 New York. 



LIGONODINA PECTINATA, new species 

 Plate 2, figs. 0. 10 



Main cusp, including the downward extension, at least as long as 

 the bar and arranged at approximately right angles to it. The main 

 specific peculiarity of the species lies in the great length and slender- 

 ness of the lateral denticles, of which there are 14 or 15. The den- 

 ticle next to the main cusp is almost at right angles to the bar and 

 the succeeding ones increase their inclination very slowly to the end 

 of the bar. The bar is sometimes slightly deflected in its terminal 

 fifth. 



OccioTtnce. — Devonian (Rhinestreet) : Slialeton, N. Y. 



Cotype.— Cat. No. 11245, U.S.N.M. 



LIGONODINA PANDERI Hinde, 1879 

 Plate 2, figs. 1, 2 



1879. Prioniodiis pandeti Hinde, Quart. Jourii. Geol. Soc. London, vol. 35, p. 

 361, pi. 16, fig. 4. 



Hinde's illustration as interpreted by us indicates a species with 

 an exceedingly strong anterior cusp and relatively delicate bar with 

 widely spaced small though probably long denticles. We have 

 found no exact match in our collection, the nearest approach being 

 the apparently young specimen here figured. 



Occnrrence. — Devonian (Ehinestieel) : Shaleton, N. Y. 



Pleisotype.~C2it. No. 11246, U.S.N.M. 



LIGONODINA DEFLECTA, new species 

 Plato 2, figs. 3, 4 



This interesting species of Avhich we figure two teeth showing 

 opposite sides, is well characterized by the curvature or deflection 

 of the bar in the prssterior half, the ndatively few mostly thick 



