TROOST *S CRINOIDS OF TENNESSEE — E. WOOD. 



55 



form here a segment of a circle or as Miller says "a horse shoe excavation." The 

 cavity for the insertion of the column is pentagonal, not deep — column cylindrical — 

 alimentary canal [lumen] pentalobate. The plates are tumid which gives it a bossed 

 surface. The plates forming the superior rim must deviate somewhat from those of 

 other species, but the gibbosity of them prevented me from detecting it. 



Observations. — The most characteristic features of this species are 

 given in Doctor Troost's description. The elevated rim around the 

 base of the arms is formed by the convex surface of the second 

 secundibrachs and the edges of the intersecundibrachs and inter- 

 brachials. 



The tumid plates of this species suggest Eucalyptocrinus decorus 

 Phillips, but the calyx is proportionally much higher. They also 

 recall Eucalyptocrinus inornatus Weller, but the latter has a lower 

 cup with more curved sides, and it lacks the elevated rim below 

 the arms. 



Formation and locality. — Brownsport limestone. Decatur County, 

 Tennessee. 



Cat. No. 39959, U.S.N.M. 



Family DOLATOCRINID^E Bather. 



Genus DOLATOCRINUS Lyon. 



Cacabocrinites Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850, p. 60 

 (nomen nudum). 



Cacabocrinus Hall, 15th Rep. N. Y. State Cab. Nat. Hist., 1862, p. 109. 



Dolatocrinus Lyon, Geol. Rep. Kentucky, III, 1857, p. 482. — Shumard, T>ans. 

 Acad. Sci. St. Louis, II, 1866, p. 367 (catalogue name). — Wachsmuth and 

 Springer, Rev. Palseocrinoidea, II, 1881, p. 124. — Miller, North Amer. 

 Geol. and Pal., 1889, p. 240.— Zittel, Text-Book Pal. (Eastman trans.), 

 1896, p. 148. — Wachsmuth and Springer, North Amer. Crinoidea Cam- 

 erata, 1897, p. 310. — Bather, A Treatise on Zoology, III, The Echinoderma, 

 1900, p. 164. 



The following is Troost's description of Cacabocrinites: 



GENERIC CHARACTERS. 



Pelvis [base] pentagonal, divided into five. 

 Costals [radials] pentagonal, five. 



Scapulars [first primibrachsj sub-hexagonal, five. The inferior angle re-entering 

 superior angle salient. 

 Arms ten. 



DOLATOCRINUS GRANDIS Miller and Gurley. 



Plate 12, fig. 2. 



Cacabocrinites sculptus Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850, 



p. 60 (nomen nudum); MSS., 1850. 

 Dolatocrinus grandis Miller and Gurley, Bull. No. 4, Illinois' State Mus. Nat. 



Hist., 1894, p. 14, pi. ii, figs. 1, 2, 3. 



The following description is by Troost : 



A low hemispherical cup having a deep, pentagonal, funnel shaped cavity for the 

 insertion of the column. This cavity is surrounded with five prominent tubercles, 



