394 SMITHSONIAN INSTITUTION 



Taxocrinus nobilis (Phillips) 

 Plate LIV , figs, ia-c 



Poteriocrinus ? nobilis Phillips, Geology Yorkshire, II, 1836, p. 205, pi. ,3, fig. 40. — (Poteriocrinites) 

 Goldfuss, Nova Acta Acad. Leop. Carol-Nat. Cur., XIX, 1839, p. 351.— D'Orbigny, Prodr. Pal. 

 Stratigraphique, I, 1849, p. 157.— (Troost MS.), Wood, Bull. 64, U. S. Nat. Mus., 1909, p. 82. 



Isocrinites nobilis Phillips, Pal. Fossils Cornwall, 1841, p. 30. — Austin and Austin, Ann. and Mag. Nat. 

 Hist., X, 1842, p. 108. 



Cladocrinites nobilis, Austin and Austin, Ann. and Mag. Nat. Hist., XI, 1843, p. 197. 



Taxocrinus nobilis, Morris, Cat. British Fossils, 1843, p. 59 (2d Ed., 1854, p. 90). — Geinitz, Verstein. 

 Grauwacken Formation in Sachsen, 1853, p. 72, pi. 20, fig. 11. — Wachsmuth and Springer, Revision 

 Palaeocrinoidea, pt. 3, 1886, p. 144. — Whidborne, Mon. Devon. Fauna S. of England, III, pt. 3, 

 Pal. Soc. London, 1899, p. 216. — Springer, Amer. Geologist, XXX, 1902, p. 91 ; Jour. Geology, XIV, 

 1906, p. 492. 



Cyathocrinus nobilis, Roemer in Bronn, Lethaea Geognostica, I, 1852-54, p. 236. 



Dimerocrinites nobilis, Pacht, Beitr. Kenntn. Gattung Dimerocrinites, 1852, p. 7. 



A very large and massive species. Crown subturbinate, almost as broad as 

 high, expanding gradually to about the level of the first IVBr, where height to 

 width is about 1.2 to 1. Calyx 1 to 1.3 at I Ax, with spread from base of 1 to 

 1.2. Arms very heavy, deeply rounded, tapering but little, and diminishing 

 much less than half at the bifurcations; divisions rather short to the third bifur- 

 cation, infolding about the fourth; sutures broadly sinuous. iBr few and small, 

 and areas narrow. Anal tube small. Surface smooth or finely tuberculose. 

 Dimensions of crown in type: height, 53 mm.; width, 45 mm.; base at column 

 facet, 10 mm. 



IBB small, hidden by column, and within the basal ring. BB small, appear- 

 ing in low pentagons beyond the column; post. B narrow above, with a small 

 excavated socket for support of first plate of the anal series. RR and lower IBr 

 rather similar in form and size, increasing gradually in width to the axillary 

 which is still wider. IBr 3; IIBr 4 or 5, nearly as wide as IBr, and over three 

 times as wide as long; IIIBr 5 or 6, and 7 or 8, about two-thirds as wide as IIBr 

 and of similar proportions; higher divisions diminishing in about the same pro- 

 portion. Anal area larger than the others ; tube evidently small, socket not en- 

 croaching on adjacent radials. iBr a few small, elongate plates in narrow 

 areas. Column not preserved, but facet large, as wide as the truncate base. 



The arms of this species are ponderous for this group, and by having the brachials of 

 each order more than half the size of their predecessor the rays increase in width in each 

 division, filling up the spaces ; this leaves little room for interbrachials, and causes the crown 

 to continue expanding almost until the arms infold. The species bears little resemblance to 

 any other, the one that seems actually nearest being that represented by some imperfect sets 

 of arms, which I have named T. pustulosis, from a substantially equivalent horizon of the 

 American Lower Carboniferous. T. nobilis was identified by De Koninck and Le Hon with 

 the specimens from the Belgian Mountain limestone on which they founded their genus 

 F orb esiocr inns; but they were doubtless led to this by the strong rays, for the specimens are 

 not otherwise similar, even generically. This is fully discussed under Forbesiocrinus, where 

 the reasons for this opinion are shown in detail. 



