ABT. 12 CLASSIFICATION OF CONODONTS ULEICH AND BASSLER 37 



LONCHODINA RECTANGULATA, new species 

 Plate 10, fig. 4 



Tooth strongly bowed with well separated denticles, the outer ones 

 rather prominent and growing gradually smaller toward the middle. 

 Species mainly characterized by the fact that the median teeth are 

 smaller than in other species of this genus and also in lacking any- 

 thing that can be compared to a major cusp. 



Occw^ence. — Mississippian (Hardin sandstone) : Mount Pleasant, 

 Tenn. 



Holotype.—Cdit. No. 11024, U.S.N.M. 



HIBBARDELLA, new genus 



Anterior and posterior ends equalty developed in structure and 

 angle to the axis of the main central cusp, the tooth thus being bi- 

 laterally symmetrical. Main cusp sharp edged, erect, and enor- 

 mously developed, especially in its length. Lateral denticles are 

 always separated, slightly curved inward, usually few, but varying 

 considerably in number and length in different species. 



Genotype. — HibhardeUa {Prionioclus) angidata Hinde, 1879. 



Range. — Upper Devonian and Early Mississippian. 



This interesting new genus is named in honor of Raymond R. 

 Hibbard, of Buffalo, N. Y., in recognition of his enthusiastic work 

 upon the conodonts and other microfossils. 



HIBBARDELLA ANGULATA Hinde, 1879 



Plate 3, figs. 1-4 



1S79. Prioniodus avgulatus Hinde, Quart-Journ. Geol. Soc. London, vol. 35, 

 p. 360, pi. 15, fig. 17. 



Even though our illustrations do not agree in all features with 

 Hinde's figure, which was based upon an incomplete specimen, we 

 feel certain of our correctness in identifying his species with the most 

 abundant form of this generic type from the same horizon. In his 

 figure the main cusp is narrower and the bar thicker, but we believe 

 these differences are due to inaccurate drafting. Besides, as shown 

 by our figures, the species is subject to considerable variation in the 

 proportions of the bar and the relative size of the denticles on the 

 latter. The main cusp has the usual character of sharp edges, one of 

 the surfaces rounded, the other with a more or less well developed 

 median angulation. The angle made by the two diverging parts of 

 the bar is usually less than a rectangle, but varies from 80 to 90 

 degrees. The number of the lateral denticles is usually about five. 



Occurrence. — Devonian (lihinestreet) : Eighteen Mile Creek and 

 Shaleton, N. Y. 



Ple.hotype^.—Vixt. No. 11295, U.S.N.M. 



