TROOST 's CRINOIDS OF TENNESSEE E. WOOD. 29 



Symhaihocrinus robustus is also recorded as from Sulphur Springs, 

 near Nashville, Tennessee; Button-mould Knob, Kentucky; and 

 Greene County, Illinois. 



Cat. No. 39940, U.S.N.M. 



Order ADUNATA Bather. 



GROUP A. 



Family PLATYCRINID^ Roemer. 



Subfamily COCCOCRININiE Bather. 



Genus COCCOCRINUS Muller. 



COCCOCRINUS BACCA Roemer. 



Plate 4, fig. 9. 



Platycrinites Ann Dixoni Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 



1850, p. 61 (nomcn nudum). 

 Coccocrinus bacca Roemer, Die Sil. Fauna d. westl. Term., 1860, p. 51, pi. iv, 



figs. 5a, b, c. — Shumard, Trans. Acad. Sci. St. Louis, II, No. 2, 1866, p. 



359 (catalogue name). — Wachsmuth and Springer, Rev. Palaeocrinoidea, 



II, 1881, p. 60 (catalogue name). — Miller, North Amer. Geol. and Pal., 



1889, p. 232, text fig. 265 (catalogue name). 



The description by Troost is as follows : 



It has a hemispherical form — a cup shaped pelvis [base] with an extremely small 

 impression for the column. Scapulars [radials] large. — Arms much projecting, which 

 gives a pentagonal appearance to the superior rim. Interscapulars [interbrachials] 

 much elevated. Surface smooth. 



Observations. — Two well preserved specimens of the dorsal cup of 

 this speeies were described by Troost as new species of the genus 

 Platycrinus. They show the second primibrachs in one or more of 

 the rays, and otherwise agree with the figures and description of 

 Roemer's species. 



Formation and locality. — This species is characteristic of the lower, 

 or Coccocrinus zone, of the Beech River formation of the Brownsport 

 limestone, as defined by Pate and Bassler [1908]. Decatur County, 

 Tennessee. 



Cat. No. 39888, U.S.N.M. 



COCCOCRINUS CONICUS (Troost). 



Plate 15, fig. 1. 



Cupellsecrinites conicus Troost, MSS., 1850. 



This species was referred by Troost to his genus Cupellsecrinites, 

 which is a synonym for Marsipocrinus Bather. His description of 

 the species is as follows: 



It is inverted conical and differs much from the general form of the species of this 

 genus [Marsipocrinus]. The pentagonal pelvis [base] forms a deep cup; the hex- 

 agonal costals [radials] are elongated — scapulars and interscapulars [first brachials and 

 interbrachials] similar to those of the other species [of Marsipocrinus]. 



