DTMEROCRINIDAE 
13 
Dimerocrinus planus new species 
Plate I, jigs, i-j 
A finely preserved species, with elongate conical calyx, smooth surface, and 
very stout arms 2 to the ray; the interbrachial system is well developed in sev- 
eral ranges, by which the brachials are incorporated to the third or fourth IIBr. 
IBB small, rarely visible from a side view. Anus directly through the tegmen. 
Column long, composed of uniformly short columnals, averaging about .2 mm. 
This is a conspicuous fossil in the Tennessee Silurian, of which besides the seven speci- 
mens figured there are a number of others showing similar characters. In having only ten 
arms it is closer to the Dudley species than to those from Gotland. 
Horizon and locality. Beech River formation, Brownsport group, Niagaran ; Decatur 
County, Tennessee. 
As collections are made, it is not always possible to give the subdivision from which the 
species is derived. For the Beech River formation, by far the greater part of the specimens 
are from the upper, Eucalyptocrinns, zone. 
Dimerocrinus milliganae (Miller and Gurley) 
Plate I, fig. 8 
Glyftastcr milliganae Miller and Gurley, Bull. lo, Illinois St. Mus., 1896, p. 87, pi. 5, figs. 7-9. 
I am figuring the type of this Tennessee species, formerly in the collection 
of Mrs. J. M. Milligan. Only the calyx is preserved, but it is well differentiated 
by the prominent ridges along the basal and radial series, more angular contour 
generally, and larger IBB. 
Horizon and locality, same as last. 
Dimerocrinus nodobasis new species 
Plate I, figs, g, lo 
Similar to D. planus but differing in the presence of sharp angular cusps 
upon the basals; the IBB are extremely small, entirely concealed by the top 
columnal. 
Horizon and locality, same as last. 
Dimerocrinus inornatus (Hall) 
Plate I, figs, ii, 12 
Glyptaster inornatus Hall, Trans. Alb. Inst., 4, 1863, p. 205; 28th Rep. New York St. Mus. 1879 p. 134 
pi. 14, figs. 1-6. — Bassler, Bibliogr. Index, 1915, p. 439. 
A massive species with strongly nodose basals, producing a stellate base. 
From the Waldron formation, Hartsville, Indiana. D. {Glyptaster) occidentalis 
(Hall), 28th Rep. New York St. Mus., 1879, p. 133, pi. 13, figs. 7-1 1, a much 
more delicate species with sharp surface sculpturing, is from the same formation 
at Waldron. 
