264 



ECHINODERMA TA. 



[OH,. ONY 



Ollacrinus, Cumberland, 1826, Appendix to 

 Reliquiae Conservata. Figured without 

 description, and subsequently declared 

 by DeKoninck & 

 LeHon to be a 

 Rhodocrinus. 

 Wachsmuth & 

 Springer claim 

 priority for this 

 name over Goni- 

 asteroidocrinus, 

 without good 

 reason, however, 

 as shown by Meek 

 in 111. Geo. Sur., 

 vol. 2, p. 217. 

 ONYCHASTER, Meek & 

 Worthen, 1868, 

 Geo. Sur. 111., vol. 

 3, p. 526. [Ety. 

 orrt/z, claw ; aster, 

 star.] A small 

 sub discoid body, 

 with five long, 

 slender, rounded, 

 flexible rays ; dor- 

 sal side of disk 

 composed of an 

 outer circle of 

 five pairs of plates 

 each, pierced 

 with an ovarian 

 pore, and two 

 inner circles of 

 five pairs each, 

 n o n p o r i ferous, 

 and surrounding 

 a central anal 

 opening; out- 

 side thtt pore plates, each pair is fol- 

 lowed by two or three pairs of inter- 

 locking transverse plates, connecting 

 with the dorsal side of the rays; farther 

 there are lanceolate plates, furrowed 

 and having pores between the inner 

 ends. Type 0. flexilis. 

 barrisi, Hall, 1861, (Protaster barrisi,) 

 Depc. New. Crinoidea, p. 18, and Geo. 

 Sur. III., vol. 5, p. 476, 

 Burlington Gr. 

 flexilis, Meek & Wor- 

 then, 1868, Geo. Sur. 

 111., vol. 3, p. 526, 

 Keokuk Gr. 



NYCHOCRINUg, Lyon & 



Casseday, 1859, Am. 

 Jour. Sci., 2d series, 

 vol. 29, p. 77. [Ety. 

 onyx, claw ; krinun, 

 lily.] Calyx low, arms 

 like the talons of a fowl ; baals 3 ; sub- 

 radials 5 ; radials 4 to 7 x 5 ; arms short, 

 branching; interradials 3 to 20; vault 

 depressed ; column large. Type O. ex- 

 culptus. 



asteriformis, Hall, 1861, (Forbesiocrinus 

 asteriformis,) Desc. New Crin., p. 9, 

 and Geo. Sur. 111., vol. 2, p. 243, Keo- 

 kuk Gr. 



distensus, Worthen, 1882, Bull. No. 1, 111. 

 St. Mus. Nat. Hist., p. 31, and Geo 

 Sur. 111., vol. 7, p. 307, Kaskaskia Gr. 



'T$$ 



FIG. 375. Onychocrinus di versus. Diagram. 



diversus, Meek & Worthen, 1866, Proc. 

 Acad. Nat. Sci. Phil., p. 256, and Geo. 

 Sur. 111., vol. 3, p. 492, Burlington Gr. 



FIG. 37*.--Onychas- 

 ter flexilis. 



FIG. 376. Onychocrinus exculptus. 



exculptus, Lyon & Casseday, 1859, Am. 

 Jour. Sci. and Arts, vol. 29, p. 78, Keo- 

 kuk Gr. 



