TKOOST's CRINOIDS OF TENNESSEE E. WOOD. 



7 



A few of the Crinoids described in this Monograph were found on the Cumberland 

 Mountains and in East Tennessee, but the generality were discovered in Middle Ten- 

 nessee, including Decatur County which lies west of the Tennessee River. 



Before terminating this introductory I must acknowledge my sincere thanks to my 

 friend Major A. Heiman who has drawn all the figures, and as appears from the work 

 itself, in a superior manner. 



I have also to request the indulgence of the reader —having been attacked by a serious 

 malady which has lasted more than 6 or 7 months whilst I was preparing it [the Mono- 

 graph] for the press; my memory and sight were more or less impaired, by which many 

 inaccuracies and mistakes may have been produced. 



DESCRIPTION OF SPECIES. 



Class CYSTOIDEA Jaekel. 

 Order DICHOPORITA Jaekel. 



A. REGULARIA Jaekel. 



Family CHIROCRINID^E Jaekel. 

 Genus CHIROCRINUS Eiehwald. 



CHIROCRINUS ANGULATUS, new species. 



Plate 8, figs. 9, 10. 



Cyathocrinites sculptus Troost, Proc. Amer. Ass. Adv. Sci., II (read 1849), 1850 



(nomen nudum); MSS., 1850. 

 Cyathocrinus sculptus Wachsmuth and Springer, Rev. Palseocrinoidea, I, 1879, 



p. 149 (catalogue name). — Miller, North Amer. Geol. and Pal., 1889, p. 236 



(catalogue name). 



The original description by Troost is as follows : 



It resembles more or less C. geometricus of Goldfuss (Tab. LVIII, fig. 5.) in its gen- 

 eral appearance, and the stellated figures on the surface are similar. Its pelvic [infra- 

 basal] plates are different, the superior angle being more acute gives a hexangular form 

 to the costals [basals], which are pentagonal in the C. geometricus. The insertion of 

 the column differs also — in the C. sculptus a deep, large, subquadrangular cavity 

 receives a cylindrical column, this cavity occupies about one half of the diameter of 

 the body. The superior rim being somewhat injured, the place for the arms and its 

 superstructure can not be determined. 



Discovered in Knox County, East Tennessee, Silurian. 



Supplementary description. — Basals four, bent abruptly upward for 

 nearly half their length to form the sides of a quadrilateral basal exca- 

 vation; second range of plates apparently five, three hexagonal, one 

 pentagonal, and the fifth not preserved; of the third range of plates 

 only two, and fragments of two more, plates are preserved. The 

 posterior side shows only fragments of plates. 



Numbering the plates as suggested by Jaekel [1899] pectinirhombs 

 are present on plates B2 to Bl, B2 to B3, B2 to Ll, B2 to L2, also on 

 plates Ll to 1/2 and L2 to L'2. 



