314 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
Dolatocrinus Marshi, var. hamiltonensis W. and Sp. 
Plate XX V. Figs. 2a, b. 
A form very similar to D. Marshi occurs in the Hamilton group, which 
we distinguish from the typical form as variety hamulionensis. The basal con- 
cavity is shallower and narrower, the radial ridges knife-like, and occupy the 
median line of the plates instead of being keel-shaped and rising gradually 
from the outer margins of the plates. The ventral disk is considerably 
lower, and but slightly convex; the orals smaller, the posterior one, which 
is very short, is placed so as to form at the anterior side the base of the anal 
tube. All plates of the disk covered by several well defined tubercles. 
Horizon and Locality.--Hamilton group, Bear grass quarries, Louis- 
ville, Ky. 
Type in the collection of Mr. Victor W. Lyon, Jeffersonville, Ind. 
Dolatocrinus Lyoni W. and Sp. (nov. spec.). 
Plate XX V. Figs. 6a, b, c, d. 
Calyx rather large, considerably wider than high. Dorsal cup more than 
twice as wide as high; the basal portions deeply impressed, forming a broad 
funnel-shaped cavity which includes one half the radials. The plates above 
the first costals curve gradually upwards, and the two upper rows stand at 
right angles to the truncated lower part of the calyx. Ventral disk low- 
pyramidal, slightly grooved toward the arm bases; the plates flat, covered 
with numerous small pustules. The plates of the dorsal cup are grotesquely 
ornamented with a variety of promimences and depressions; some of them 
elevated into sharp, very conspicuous, transversely rounded nodes, others 
sharply pointed ; and from all of them somewhat irregular, subangular ridges 
pass out to the margins of the plates, connecting with similar ridges from 
adjoining plates. The plates of the rays have no nodes, and but few ridges 
proceed upwards; those directed laterally form a well defined pentagon 
around the basal concavity. In the upper part of the calyx the nodes cover 
the greater part of the plates, and the ridges are merely indicated at their 
outer margins. 
Basals small, restricted to the bottom part of the cavity. Radials nearly 
as large as the two costals together. First costals quadrangular, narrower 
than the radials; the second pentangular, supporting upon one side an axil- 
