98 



BULLETIN 64, UNITED STATES NATIONAL MUSEUM. 



Family ENCRINIDiE Bather. 

 Genus STEMMATOCRINUS Trautsehold. 



STEMMATOCRINUS TRAUTSCHOLDI Wachsmuth and Springer. 



Plate 7, figs. 12, 13, 14. 



Cyathocrinites robusius Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850, 



p. 61 (nomen nudum); MSS., 1850. 

 Cyathocrinus robustus Wachsmuth and Springer, Rev. Palseocrinoidea, I, 1879, 



p. 149 (catalogue name). — Miller, North Amer. Geol. and Pal., 1889, p. 236 



(catalogue name). 



Stemmatocrinus trautscholdi Wachsmuth and Springer, Rev. Palseocrinoidea, 

 III, 1886, p. 256, pi. ix, figs. 7, 8.— Miller, North Amer. Geol. and Pal., 

 1889, p. 282 (catalogue name).— Weller, Bull., No. 153, U. S. Geol. Surv., 

 1898, p. 601 (catalogue name). 



The description by Troost is as follows: 



It is almost hemispherical, smooth and remarkably strong, the plates being very 

 thick as is seen in the figure. The pelvis [base] is small — no divisions preceptible. 

 The column is cylindrical, the costals [basals] short pentagonal and the scapulars 

 [radials] broad and the whole of the superior margin excavated for the reception of 

 the arms. No interscapulars [interbrachials] are visible. 



Observations. — The description by Wachsmuth and Springer cited 

 above gives all that is known of the species. 



The four specimens in the Troost collection preserve only the 

 dorsal cup to the top of the radials. 



Formation and locality. — Keokuk horizon of the Tullahoma forma- 

 tion. Harpeth River and White's Creek Springs, Davidson County, 

 Tennessee. 



Cat. No. 39972, U.S.N.M. 



Genus ERISOCRINUS Meek and Worthen. 



ERISOCRINUS (?) BIPARTITUS (Troost). 



Plate 6, figs. 8, 9. 

 Donacicrinites bipartitus Troost, MSS., 1850. 

 The following description is by Troost : 



The only difference between this and D. simplex seems to be the elevated ridge 

 which runs longitudinally over the joints composing the hands. In this the cup is 

 complete and shows the construction of the pelvis and superior plates. 



Decatur County, Tennessee. 



Observations. — Doctor Troost's specimen of this species has been 

 misplaced and having only the figures and his somewhat meager 

 description for the determination of the species it is placed with 

 doubt in the genus Erisocrinus. The general form of the crinoid 

 suggests that of Erisocrinus whitei Meek and Worthen, but the 

 dorsal cup of the latter is much lower and the first arm plates are 

 higher. 



