TROOST *S CRINOIDS OF TENNESSEE — E. WOOD. 



41 



Family HEXACRINID^E Wachsmuth and Springer. 



Genus TALAROCRINUS Wachsmuth and Springer. 



Dsemonocrinites Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850, p. 62 



(nomen nudum), MSS., 1850. 

 Doliolocrinites Troost, MSS., 1850. 



Dichocrinus Shumard (in part), (not Minister) Trans. Acad. Sci. St. Louis, I, 

 1857, p. 71. — Casseday and Lyon (in part), Proc. Amer. Acad. Arts and 

 Sci., V, 1862, p. 16. 



Talarocrinus Wachsmuth and Springer, Rev. Palseocrinoidea, II, 1881, p. 85. — 

 Miller, North Amer. Geol. and Pal., 1889, p. 285.— Zittel, Text Book of 

 Pal. (Eastman trans.), 1896, p. 140. — Bather, A Treatise on Zool., III, The 

 Echinoderma, 1900, p. 159. 



The following is a description of Dsemonocrinites by Troost: 



Generic characters — Pelvis [base] divided into two parts. 



I found it rather difficult to select a name for this heterodox crinoid — I could not 

 compare it with any natural object, and having two horns I could not dedicate it to 

 any of my scientific friends — so I have put it under the patronage of one who is gener- 

 ally represented with such ornaments. 



The following description of Doliolocrinites is by Troost: 



Generic characters — Pelvis [base] hemispherical composed of six [two] subpen- 

 tagonal plates supporting six subpentagonal scapulars [radials and anal plate]. 



TALAROCRINUS SYMMETRICUS (Lyon and Casseday). 



Plate 4, figs. 1, 2. 



Dsemonocrinites cornutus Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 

 1850, p. 62 (nomen nudum); MSS., 1850. 



Dichocrinus symmeiricus Lyon and Casseday, Proc. Amer. Acad. Arts and Sci., 

 Boston, V, 1862, p. 20. — Shumard, Trans. Acad. Sci. St. Louis, II, No. 2, 

 1866, p. 367 (catalogue name). 



Dichocrinus elegans Lyon and Casseday, Proc. Amer. Acad. Arts and Sci., Bos- 

 ton, V, 1862, p. 22. 



Talarocrinus symmetricus Wachsmuth and Springer, Rev. Palseocrinoidea, II, 

 1881, p. 87 (catalogue name). — Miller, North Amer. Geol. and Pal., 1889, 

 p. 285 (catalogue name). — Wachsmuth and Springer, North Amer. Crinoidea 

 Camerata, 1897, p. 786, pi. lxxviii, figs. 4a, h, and 5. — Weller, Bull. 

 No. 153, U. S. Geol. Surv., 1898, p. 624 (catalogue name). 



Talarocrinus elegans Wachsmuth and Springer, Rev. Palseocrinoidea, II, 1881, 

 p. 87 (catalogue name). — Miller, North Amer. Geol. and Pal., 1889, p. 285 

 (catalogue name). 



The following description is by Troost : 



Pelvis [base] irregular, more or less hexagonal, divided into two parts. 

 Costals [radials and anal plate], six, subhexagonal, almost spherical, forming, con- 

 nected, an irregular hexagon with rounded angles. 



Column cylindrical with a circular alimentary canal [lumen]. 



Capital integument [tegmen] — in the form of a hemispherical dome having two 

 horn-shaped projections at the sides and a small, pointed protuberance at the summit. 



At the base of this capital integument are 5 or 6 apertures divided longitudinally by 

 a septum, probably the apertures for the arms — above one of these apertures, near the 

 summit is another aperture, probably the mouth [anus]. 



