TKOOST'S CEINOIDS OF TENNESSEE E. WOOD. 



67 



which are composed arms and hands, the horseshoe formed joints, fifteen in number, a 

 forming the upper rim of the body which is covered by a cone or coronal integument, 

 surrounded with large projecting tubercles some of which are flattened and divided 

 into three points. This capital integument terminates in an ample proboscis — and 

 this proboscis, as I have never observed in any of the crinoids, is internally divided 

 into three parts as if it was composed of three tubes having each a circular aperture [?]. 

 This division is not accidental. I found it in all perfect probosces of this species. 

 The proboscis is only 6 mil. m. long. 



I found them at White's Creek Springs only, where the fragments of it are not uncom- 

 mon, but I found only one perfect specimen. 



Observations. — Doctor Troost's specimens of the species are large 

 and characteristic individuals. The appearance of partitions within 

 the anal tube, described by Troost, is produced in one of his speci- 

 mens by the presence of two large, hollow spines which have been 

 broken off near the point where the tube is itself broken off. The 

 three apertures thus produced were mistaken by Troost for parts of 

 the same tube. 



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

 tion. White's Creek Springs, Tennessee. Also found at Pilot Knob, 

 near Louisville, and Barren County, Kentucky; Montgomery County, 

 Indiana. 



Cat. No. 39891, U.S.N.M. 



ERETMOCRINUS SPINOSUS (Miller and Gurley). 



Plate 11, figs. 1, 2. 

 Actinocrinites marineri Troost, MSS., 1850. 



Batocrinus spinosus Miller and Gurley, Bull. No. 6, Illinois State Mus. Nat. 

 Hist., 1895, p. 5, pi. i, figs. 1, 2, 3.— Weller, Bull. No. 153 U. S. Geol. Surv., 

 1898, p. 134 (catalogue name). 



The following description is by Troost : 



The cup of this crinoid resembles more or less that of the A. cornutus mihi, [Eret- 

 mocrinus praegravis Miller], but it is more longitudinally compressed. It differs prin- 

 cipally in the form of its capital integument which is low and in the form of a dome in 

 the A. cornutus, whereas it is elongated and conical in the A. marineri and its proboscis 

 is tuberculated to its very summit, whereas the summit of the A. cornutus is without 

 tubercles. 



It was discovered by Mr. George Mariner in Cannon County, Tennessee, Carbon- 

 iferous. 



Observations.— The single specimen representing Doctor Troost's 

 species agrees exactly with that of Miller and Gurley except that it 

 has three arms in the anterior ray instead of two. 



Both Troost and Miller and Gurley call attention to the close resem- 

 blance between this species and Eretmocrinus praegravis Miller. The 



a Such is the case with the specimen here described. I have a mutilated one 

 which shows that the two arms proceeding from the scapulars are both divided form- 

 ing four hands, if this subdivision continues, which the imperfect state of the specimen 

 does not show, it would give 20 of these joints, while the specimen here described has 

 only 15. — Troost. 



