TROOST *S CRINOIDS OF TENNESSEE — E. WOOD. 75 



365, 367, the name Uperocrinus was abandoned by these authors 

 and the species formerly included under it referred to Batocrinus as 

 group A, which is characterized by having the arm openings directed 

 outward instead of upward. Another group, B, is described as hav- 

 ing the arm openings directed upward, and to this group Actinocrinus 

 nashvillse (Troost) Hall is assigned. Bather [1900, p. 168] revived 

 Meek and Worthen's name Uperocrinus, changing it, however, to 

 Hyperocrinus, and gave Lobocrinus as a synonym of it, but as the 

 earlier name was abandoned by its authors it seems that Lobocrinus 

 should hold. Lobocrinus is, moreover, used in a somewhat different 

 sense from that of Uperocrinus. 



LOBOCRINUS NASHVILLE (Hall). 



Plate 6, figs. 1, 2, 3, 4. 



Actinocrinites nashvillse Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850, 



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

 Actinocrinus nashvillse Hall, Geol. Surv. Iowa, I, Pt. 2, p. 609, pi. xv, fig. 4, pi. 



xvi, figs. 4a, 6.— Shumard, Trans. Acad. Sci. St. Louis, II, No. 2, 1866, p. 



346 (catalogue name). — Quenstedt, Handb. d. Petrefactenkunde, 1885, 



pi. lxxvii, fig. 2. 

 Batocrinus nashvillse Wachsmuth and Springer, Rev. Palseocrinoidea, II, 1881, 



p. 167 (catalogue name). — Miller, North Amer. Geol. and Pal., 1889, p. 228 



(catalogue name). — Worthen, Geol. Surv. Illinois, VIII, 1890, p. 85, pi. xni, 



fig. 5. — Keyes, Missouri Geol. Surv., IV, 1894, p. 183. 

 Lobocrinus nashvillse Wachsmuth and Springer, North Amer. Crinoidea Cam- 



erata, 1897, p. 435, pi. xxxi, fig. 1.— Weller, Bull. No. 153, IT. S. Geol. Surv., 



1898, p. 332 (catalogue name). 



The following description is by Troost: 



It has the form of a vase like the A. urna [Batocrinus grandis] but differs from it in 

 having a broader base and the cup extending more regularly towards its superior rim, 

 the apertures for the insertion of the fingers [arms] lying on the level of the coronal 

 integument, so that by taking a top view of the body we see the 20 apertures, which 

 are invisible when a lateral view is taken. Also the coronal integument rises more 

 abruptly and the proboscis is much wider. This proboscis distinguishes it eminently 

 from the A. urna which has a slender proboscis, — in this species it is very capacious, 

 it is composed of four longitudinal ranges of polygonal plates which are pointed. The 

 plates of the cup are not much elevated, some are almost smooth, those of the coronal 

 integument on the contrary are much elevated in the centre, almost pointed. 



Observations. — The first published description of this species was by 

 James Hall, although, on account of Hall's reference to Troost's 

 manuscript description then in his possession, the species is usually 

 accredited to Troost, who wrote the first description of it. It has 

 since been several times described, by Worthen [1890], Wachsmuth 

 and Springer [1897], etc. 



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

 mation. White's Creek Springs, Davidson County, Tennessee; 

 Button Mould Knob, Kentucky; Keokuk, Iowa; Warsaw and Nau- 

 voo, Illinois. 



Cat. No. 39894, U.S.N.M. 



