TROOST *S CRINOIDS OF TENNESSEE E. WOOD. 23 



Troost's species has relatively long arm plates, and is more closely 

 related to Heterocrinus canadensis than to Meek's variety, with which 

 it corresponds in size. 



Formation and locality. — Lower part of Trenton formation. Frank- 

 fort, Kentucky. 



Cat. No. 39921, U.S.N.M. 



Family PISOCRINID^E Angelin. 

 Genus PISOCRINUS de Koninck. 



PISOCRINUS MILLIGANI Miller and Gurley. 



Haplocrinites hemisphaericus Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 



1850, p. 61, (nomen nudum). 

 Pisocrinus gorbyi Miller (in part), 17th Rep., Indiana Geol. Nat. Res., 1892, p. 640, 



pi. vi, figs. 21, 22, 23. 

 Pisocrinus milligani Miller and Gurley, Bull. No. 7, Illinois State Mus. Nat. 



Hist., 1895, p. 80, pi. v, figs. 27, 28. 



Troost referred this species to Haplocrinus, and his remarks merely 

 distinguish the specimen from Haplocrinus stellaris Roemer and H. 

 mespiliformis Goldfuss. His figures are misleading, as they represent 

 a regular arrangement of suture lines which does not appear on the 

 specimen. 



The single specimen in the Troost collection represents the dorsal 

 cup only, and the suture lines are not sufficiently distinct to show 

 the arrangement of the plates, but in all the characteristics winch 

 appear it is identical with the Pisocrinus milligani of Miller and Gurley. 

 On one of Miller and Gurley's figures, fig. 27, pi. 5, the shading is 

 reversed. The fact that the mortise occurs on the projecting lobe of 

 the radial in their specimen, as well as in that of Troost, is shown by 

 their description, and by an earlier figure of Miller [1892, pi. 6, fig. 23]. 



Formation and locality. — Brownsport limestone. Decatur County, 

 Tennessee. 



Cat. No. 39941, U.S.N.M. 



Family CATILLOCRINID^ Wachsmuth and Springer. 

 Genus CATILLOCRINUS Shumard. 



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

 {nomen nudum); MSS., 1850. 



Catillocrinus Shumard, Trans. Acad. Sci. St. Louis, II, No. 2, 1866, p. 357. — Meek 

 and Worthen, Geol. Surv. Illinois, III, 1868, p. 465; V, 1873, p. 504 — 

 Zittel, Handb. d. Pal., I, 1879, p. 348. — De Loriol, Palaeontologie Fran- 

 caise, Crinoids, XI, 1882, p. 46. — Wachsmuth and Springer, Rev. Palseo- 

 crinoidea, III, 1885, p. 268.— Miller, North Amer. Geol. and Pal., 1889, 

 p. 231.— Bather, A Treatise on Zool., Ill, The Echinoderma, 1900, p. 150. 



Nematocrinus Meek and Worthen, Proc. Acad. Nat. Sci. Phila., 1866, p. 251. 



The following is Troost's original description: 



Column cylindrical. Alimentary canal [lumen] pentagonal or penta-petalous. 



