PALEONTOLOGIC CONTRIBUTIONS 43 



On the abactinal side the radial plates form a continuous column 

 of narrow, elongate plates, as in Lepidasterella ; and also the supra- 

 marginal plates which alternate with them are as in that genus. 

 The upper edges of the inframarginals form a narrow marginal 

 fringe of the rays. 



The preservation of the specimens which are interior molds, 

 has left us in doubt, especially in regard to our correct under- 

 standing of the ventral or actinal structure, and we consider it 

 possible that this genus may some day prove to have an entirely 

 different taxonomic position. 



Genoholotype and only species. Lepidasterina graci- 

 1 i s nov. 



Lepidasterina gracilis nov. 

 Plate 10, figures 1-4 



Description. Rays eight to nine, long and slender. Length of 

 ray in one specimen 48 mm and basal width 2.5 mm ; length in the 

 other specimen 21 mm and width 2 mm. Disk very small and only 

 formed by the bases of the rays ; its radius about 10 mm. 



The actinal side of the rays shows in no case the ambulacrals, 

 the ambulacral groove being very narrow ; the adambulacral plates 

 are slender, elongate ossicles with straight margin on the inner 

 and slightly concave margins on the outer side, where they are 

 slightly widened toward the extremities. They may be alternate or 

 opposite in different specimens. The inframarginal plates which 

 alternate with them are of similar shape, subrectangular, as seen 

 from below, with slightly concave longer margins. They bear a 

 long spine on the lateral margin and exhibit spine-bases on the 

 underside near the distal suture. ' The ossicles of the oral armature 

 appear to have been slender, V-shaped. The abactinal side of the 

 disk is not well preserved but seems to have been very spinous. 

 The rays show a median column of narrow, subelliptic radials, 

 flanked on either side, without interruption by any accessory 

 plates, by the supramarginal plates that are subquadratic in outline, 

 quite tumid of form and bear spines on the outer distal angle. 

 The upper portions of the inframarginals form an outer fringe of 

 narrow ossicles. 



Horizon and locality. Lower Chemung beds at Avoca, Steuben 

 county, N. Y. 



Remarks. The material consists of only two specimens, neither 

 of which is especially well preserved. The smaller shows distinctly 



