INVEBTEBKATES. 327 



Descriptions of now Carboniferous Echinoderms, by A. H, Worthen and S. A. Miller. 



CLASS ECHINODERMATA, 



ORDER ASTEROIDEA. 



FAMILY PAL^ASTERID^E. 



COMPSASTER, n. gen. 



(Ety. Kompsos, elegant; aster, a star.) 



Body stellate ; central area or disc comparatively small ; rays large, 

 long, more or less fusiform; grooves deep and bordered by numer- 

 ous thin, subcircular, adambulacral plates. The ventral side of the 

 typical species shows about six rows of plates upon each side of 

 the ambulacral furrows, which have a regular, transverse, as well 

 as longitudinal arrangement. 



This genus is distinguished from all others in the family by the 

 number and form of the adambulacral plates, by the great number 

 of disc plates upon each side of the ambulacral furrows, and by the 

 general form of the body and rays. 



COMPSASTER FORMOSUS, Sp. nov. 



PI. XXXI: Fig. 2 a, ventral side, natural size; flg. 2 I, section of a ray enlarged two di- 

 ameters. 



Body deeply stellate ; central disc comparatively small ; rays rigid, 

 large, fusiform, more than twice as long as the diameter of the cen- 

 tral disc, and terminating abruptly in an obtuse point. The typical 

 specimen furnishes the following measurements: Diameter of the 

 body, T V - inch ; length of ray from central part of disc, l.^V inches; 

 diameter of the ray at its junction with the body, T 4 oV inch. 



Ambulacral grooves deep; ossicles rather small; adambulacral 

 plates very numerous, and consisting of a series of thin plates upon 



