158 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 



edge of the disk, more actinal than abactinal. Inframarginals or 

 supramarginals bounding the rays. 

 Contains : 



Lepidaster Forbes. 

 Eelianthaster Koemer. 

 Lepidasterella, new genus. 

 Remarks. — For a discussion as to why there are multi-rayed — that 

 is, more than the normal five-rayed — asterids, see the family Palae- 

 osolasteridse. 



Genus LEPIDASTER Forbes. 



Lepidaster Forbes, Mem. Geol. Surv. United Kingdom, British Org. Rem., 

 dec. 3, 1850, p. 1, pi. 1, figs. 1-3. — Wright, Mon. British Foss. Echinod., 

 Oolitic, vol. 2, pt. 1 (Palseontogr. Soc. for 1861), 1862, p. 35.— Woodward, 

 Geol. Mag., dec. 2, vol. 1, 1874, p. 9.— Zittel, Handb. Pal., vol. 1, 1879, 

 p. 454.— Stxjrtz, Palseontographica, vol. 36, 1890, p. 222, pi. 28, figs.19-20; 

 Verh. naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 52, 72. 



Generic description. — Disk very large, over 50 mm. in diameter, 

 and apparently composed of heavy, closely set, polygonal plates. 

 Rays 13 in number, fairly stout, not slender, and tapering fairly 

 rapidly in the distal half. R = 52 mm. , r = 25 mm. A little more than 

 half the length of the rays extends beyond the disk. 



Actinally, the rays are bounded on each side of the very narrow 

 ambulacral furrow by two columns of strong, tumid, closely ad- 

 joining, transversely oblong, adambulacral and inframarginal plates. 

 The latter are also the marginals for the abactinal side. The adam- 

 bulacrals are tuberculate and probably bore small spines; there 

 are 25 ossicles in each column. Ambulacrals unknown, but the 

 arrangement of the adambulacrals indicates that they were sUghtly 

 alternate. 



Madreporite and interbrachial areas unknown. 



Abactinally little is known. The rays are described as having 

 "numerous small polygonal nearly flat ossicula, closely set, and of 

 various sizes." To judge by similar rays in other genera, it would 

 appear that Lepidaster may have had radial and supramarginal 

 columns of ossicles. 



Genoholotype and only species. — L. grayi Forbes. The holotype 

 was found in the quarries of Wenlock limestone in the Castle Hill at 

 Dudley, England. 



Observations. — Forbes's illustration leads the writer to believe 

 that the abactinal plates have been deranged and that originally 

 the larger pieces were arranged in supramarginal columns, while the 

 smaller ones composed the radial row of ossicula. This type of 

 structure generally goes with the actinal arrangement as here seen in 

 Lepidaster, a duplicate of the same structure in Hudsonaster, Palse- 

 aster, and Mesopalseaster. Stiirtz compares the abactinal skeleton of 



