270 



ECHINODERMA TA. 



[pla. 



pyriformis, Ringneberg, (Triacrinus pyri- 

 formis,) Proc. Acad. Nat. Sci. Phil., p. 

 145, Clinton Gr. 

 Platycrinus, Miller, 1821, Nat. Hist, Cri 

 noidra, p. 73. [Ety. pltttys, flat; krinon 

 lilv.] Calyx bowl-shaped ; basals 3 

 primary radials 2x5; regular inter 

 radials 1x4; azygous interradials, 

 large and 3 small; dome elevated 

 arms 10 to 35, bearing pinnules 

 column large and twisted. Type P 

 lsevis. 



aequalis, Hall, 1861, Desc. New. Crin., p 

 117, and Ceo. Bur. 111., vol. 5, p. 456, 

 Burlington Gr. 



americanus, Gwen & Shumard, 1850, 

 Jour. Acad. Nat. Sci. Phil., 2d ser., vol. 

 2, p. 89, Burlington Gr. 



anndixoni, Troost. Not defined. 



Fig. 392.— Platycrinus asper. Diagram. 



asper, Meek & Worthen, 1861, Proc 



Acad. Na*. 8ci. Phil., p. 129, and Geo 



Sur. 111., vol. 3, p. 468, Burlington Gr. 

 bedfordensis, Hall & Whitfi Id, 1875, 



Ohio Pal., vol. 2, p. 161, Erie Shales, 

 bloom fieldensis, 8. A. Miller, 1880, Jour. 



Cin. Soc. Nat. Hist., vol. 2, p. 257, 



Keokuk Gr. 

 bonoensis, White, 1878, Proc. Acad. Nat. 



Sci. Phil., p. 30, and Cont. to Pal., No. 



6, p. 160, Keokuk Gr. .-■■■ : 'OOf7r = ? 



brevinodus, Hall, 1861, Desc. New Cri- .,>.*.>£>' '" L^J 



noidea, p. 4, and Bost. Jour. Nat. *' '"' 



Hist., vol. 7, p. 286, Keokuk Gr. 

 burlingtonensis, Owen & Shumard, 1850, 



Jour. Acad. Nat. Sci., 2d ser., vol. 2, p. 



60, Burlington Gr. 

 calyculus, Hall, 1861, Desc. New Crin., 



p. 16, Burlington Gr. 

 canaliculatus, Hall, 1858, Geo. Sur. Iowa, 



vol. 1. pt. 2, p. 539, Burlington Gr. 

 cavus, Hall, 1858, Geo. Sur. Iowa, p. 527, 



Burlington Gr. 

 clytis. Hall, 1861, D^sc. New Crin., p. 4, 



and Bost. Jour. Nat. Hist., vol. 7, p. 



285, Burlington Gr. 

 contritus, Hall, 1863, 17th Rep. N. Y. St. 



Mus. Nat. Hist,, p. 54, and Ohio Pal., 



vol. 2, p. 166, Waverly Gr. 

 corporiculus, Ringueberg, 1886. Bull. Buf. 



Soc. Nat. Sci., vol. 5, p. 12, Niagara Gr. 



Not properly defined. 



corrugatus, Owen & Shumard. 1850, Jour. 



Acad. Nat. Sci., vol. 2, p. 59, Burling- 

 ton Gr. 

 depreams, Owen. Not defined, 

 discoideus, Owen & Shumard, 1850, Jour. 



Acad. Nat. Sci., 2d ser., vol. 2, p. 58, 



Burlington Gr. 

 eboraceus, Hall, 1862, 15th Rep. N. Y. St. 



Mus. Nat. Hist,, p. 119, Ham. Gr. 

 elegans, Hall, 18'il, Desc. New Crin., p. 4, 



and Bost. Jour. Soc. Nat. Hist., vol. 7, 



p. 285, Burlington Gr. 

 eminulus, Hall, 1861, Desc. New Crin., 



p. 17, Burlington (Jr. 

 eriensis, Hall, 1862, 15th Rep. N. Y. St. 



Mus. Nat Hist., p. 119, Ham Gr. 

 excavatus, Hall, 1861, Desc. New Crin., 



p. 4, and Bost. Jour. Nat. Hist., vol. 7, 



p. 286, Burlington Gr. 

 exsertUH, Hall, 1858, Geo. Sur. Iowa, p. 



539, Burlington Gr. 

 faberi, n. sp. Calyx bowl-shaped ; sub- 

 cylindrical above ; 



attaching point for 



column projecting 



below ; base marked 



by three keel- 



responding with the 



sutures between 



ttie basal plates, and 



along which the 



sutures may be dis 



tinguUbed ; radials 



large, width a little greater than height ; 



cicatrix for attachment of arms in the 



center of the upper face of each radial, 



and occupying about one-third of the 



width of the plate ; surface marked by a 



row of tubercles radiating on each 



Fia. 



:s— 1'liityorlnut 

 faberi, x 2. 



Fia. 394— Platycrinus hemisphericus. Diagram. 



plate from the angle of union of basal 

 and radial plates, and also a few scat- 

 tering tubercles; collected in Scott 

 County, West Va., in the St. Louis or 

 Kaskaskia Gr. 



