34 BULLETIN 115, UNITED STATES NATIONAL MUSEUM. 



In size B. grandis is typically a very large species, maximum speci- 

 mens attaining 35 mm. in height and 60 mm. in width, the average 

 ratio of height to widtli being about as 1 to 1.6. But few approach 

 a minimum of 20 mm. wide; a specimen of that size, abnormal, like 

 the three above mentioned, m havmg a single iBr in the second 

 range of some interrays, was mistaken by Miller and Gurley for Z). 

 marshi, and figured as such in their endeavor to improve upon 

 Lyon's original description of the species. Misled by their misi- 

 dentification, Rowley figured a specimen of this species in 1903 as 

 D. marshi, but afterwards in 1906 decided to make a new species of it, 

 namely, D.fossatus. His ID. excavatits, var. incarinatns was separated 

 because lacking a keeled radial ridge, and having a high tegmen, 

 both being individual variations observable in a large series of 

 specimens. 



As early as 1849 this species was recognized by the pioneer western 

 geologist and paleontologist, Gerard Troost, of Tennessee, who pre- 

 pjired an elaborate description and good figure of it under the name 

 Cacahocrinites sculptus, announced by Prof. Louis Agassiz at the 

 meeting of the American Association for the Advancement of Science 

 for that year. This would have been the type of the genus but for 

 the long delay in publication, by which Troost 's priority as to this 

 and many other well-known crinoids was lost.'^ 



Miller and Gurley ^^ give the horizon of D. grandis as Hamilton; 

 but it is well known to all the collectors that the specimens of this 

 species occur only in the Onondaga formation (usually labeled 

 "LTpper Helderberg"), below the hydraulic beds which constitute 

 the recognized boundary in that locality. Mr. Greene in a letter to me 

 of November 9, 1903, in reply to an inquiry touching the horizon of 

 this and other species, informed me that he furnished Mr. Gurley the 

 types of D. grandis and D. spinosus, and that both came from the 

 "Upper Helderburg" at Louisville. 



Horizon and locality. — Onondaga (Jeffersonville) limestone: Louis- 

 ville, Kentucky, and vicinity. 



DOLATOCRINUS SPINOSUS Miller and Gurley. 



Plate 8, figs. 1-7; plate 10, fig. 1. 



Z)oZatomm<s spinosws Miller and Gurley, Bull. 4, 111. St. Mus., 1894, p. 8, 



pi. 1, fig. 4.— Rowley in Greene, 1903, p. 164, pi. 48, fig. 4. 

 Dolatomnus curriei Rowley in.Greene, 1903, p. 143, pi. 42, figs. 1-fi. 



This is one of the two leading species of the Onondaga beds at 

 Louisville (although erroneously stated by its authors to be from the 

 Hamilton). Miller and Gurley had a poor specimen, in which the 

 surface sculpture was not preserved; but there was enough other 



" See the account of this by Miss Wood, Bull. 64, U. S. National Museum, 1909, pp. 1-7. 

 '^ Bull. 4, p. 16. 



i 



