TROOST *S CRINOIDS OF TENNESSEE E. WOOD. . 27 



SYMBATHOCRINUS TROOSTI, new species. 



Plate 9, fig. 9. 



Synbathocrinites tennesseese Troost (in part), Proc. Amer. Ass. Adv. Sci., II, 

 No. 2 (read 1849), 1850, p. 61 (nomen nudum); MSS., 1850. 



The figures and the main portion of Troost's description of Sym- 

 bathocrinus tennesseese are from the specimens now labeled S. troosti, 

 therefore all of the description except a portion referring to the 

 young of S. tennesseese is reproduced below. 



The original description is as follows: 



Pelvis [base] circular, divided into three parts (visible in young specimens) with 

 five, rounded [slightly curved] excavations in which are placed: scapulars [radials] 

 five, more or less wedge shaped, tumid, giving a pentagonal form to the cup. 



Column cylindrical, radiating [crenulated] around the margin of the articulating 

 surface, and circular alimentary canal [lumen]. 



Supplementary description. — Basals three, radials five, arm plates 

 not preserved. The angle of divergence between the base and sides 

 of the calyx is about 127°, producing a low, spreading cup. Surface 

 apparently smooth. The species is characterized by the distinctly 

 flattened central portion of the radials and the broad, shallow 

 bevelling of these plates on either side of the sutures. 



Observations. — The species is distinguished from Symbathocrinus 

 tennesseensis by its greater size, flattened radials, and sunken sutures; 

 and from S. robustus by the form of the radials and the low, spreading 

 calyx. 



Formation and locality. — Brownsport limestone. Decatur County, 

 Tennessee. 



Cat. No. 39980, U.S.N.M. 



SYMBATHOCRINUS GRANULATUS Troost. 



Plate 9, figs. 4, 7, 8. 



Synbathocrinites granulatus Troost, Proc. Amer. Ass. Adv. Sci., II, 1850, p. 61 



(nomen nudum); MSS., 1850. 

 Synbathocrinus granulatus Shumard, Trans. Acad. Sci. St. Louis, II, No. 2, 1866, 



p. 397 (catalogue name). 

 Symbathocrinus granulatus Wachsmuth and Springer, Rev. Palaeocrinoidea, III, 



2d sec, 1886, p. 166 (catalogue name). 



The original description is as follows: 



It differs from S. tennesseese in having its costals [radials] more elevated, and more 

 convex longitudinally, which elevations terminate in a bevel at the rim of the cup, 

 and in having a granulated surface. 



Observations. — The species is characterized by its small size, 

 tuberculate surface, and the form of the radials. The central portions 

 of the latter are strongly convex, bevelled above, producing semi- 

 circular flat or concave surfaces between the center and the upper 

 margin of the radials. It closely resembles Symbathocrinus angularis 



