THE FOSSIL CKINOID GENUS DOLATOCRINUS AND ITS ALLIES. 29 



S. S. Lyon gives the horizon of D. lacus as '' above the hydrauHc 

 beds," but says that some specimens occurred at the base of the 

 hydrauhc Hmestone. All the specimens in the Lyon collection when 

 I purchased it, including the type, were labeled "LTpper Helderberg;" 

 and Colonel Lyon's son, Victor W. Lyon, who collected many of 

 them, said that to his personal knowledge they came from the " upper 

 part of the Nudeocrinus bed." George K. Greene labeled all the 

 specimens which I obtained from him as "Upper Helderberg;" and 

 the occurrence of the species at Columbus, Ohio, confirms the horizon 

 as Onondaga. The statement in Lyon's text must have been due to 

 oversight or confusion of notes. 



DOLOTACRINUS PYRAMIDATUS, new species. 



Plate 5, figs. 8-11. 



Of the type of D. lacus, but with base enlarged to a width greater 

 than that of the calyx at the level of the arms, so that the slope of 

 the nearly straight sides is inward at less than a right angle. The 

 first primibrach and first interbrachial are bent inward below to 

 form a part of the flat base, the calyx resting upon the small nodes 

 upon these plates. This very unusual contour occurs in three well 

 marked specimens; the largest of them, which abnormally lacks an 

 arm in one ray, is about 22 mm. high by 28 mm. wide at the arm 

 level, and 31 at the base. Pinnule pores are very conspicuous, 2 

 and 4 to the interspaces. 



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

 ville, Kentucky. 



DOLATOCRINUS ORNATLS Meek. 



Plate 6, figs. 1-4, 



Dolatocrinus ornatus Meek, Proc. Acad. Nat. Sci. Philadelphia, 1871. p. 57. — 

 Miller and Gurley, Bull. 4, 111. St. Mus., 1894, p. 181, pi. 2. figs. 7-9. 



Described by Meek without illustration, but well figured by Miller 

 and Gurley, their figure corresponding in all essentials with the type 

 in Columbia University, which is here figured for the first time. 

 The species is not uncommon in the Onondaga rocks at Columbus, 

 Ohio, and I have it also from western New York. From the Ohio 

 locality I have a number of good specimens, averaging somewhat 

 larger than that of Miller and Gurley's figures. It is, however, 

 typically a small species, and differs decidedl}^ from the other small 

 Onondaga species, D. lacus, in the relatively lower, broader, and 

 less angular calyx, and in its peculiar sculpturing by means of very 

 fine radiating costae, which become bent and wrinkled in various 

 Avays, producing a sort of vermicular style of ornament. In most 

 specimens a low continuous radial ridge is defined, but in some it is 

 entirely wanting. The tegmen is remarkablv constant among the 



