Tl, CRINOIDEA. _ TL 
VII. Description of new Fossm CrrnomEa poe the Pa- 
rma Rocks of the Western and Southern portions . 
United States. By B. F. Suumarp, M.D. 
Genus Dicnocrinus. 
e formula of the genus Dichocrinus of —- as given 
by D De Koninck and . Hon,* is as follows? 
Basal pieces 
Radial ‘“ ‘? of feicon) one is large xs. 
7 Riga cunknow 
« 1 known, rae large, reposing on the aie 
pyar 10. 
The anatomical structure of a very perfect specimen of this ge- 
mus, — we are about to describe, corresponds only in part 
—— above formula. In ou our fossil we find « base of two pie- 
ing a tircle of five large radials, and one large anal 
piece, a a in all the known species of the genus. The radials, 
, are not repeated, but each one iennaodinily gives rise 
to -_ naridietehe pieces, which are pentagonal, and in tarn sup- 
le arms 
most perfect example of the genus, represent 
the number of radial pieces to be twenty, i.e. five repeated four 
times. 
In Dichocrinus ovatus, described by Dr. Owen-end the author 
of this paper, there appear to be but ten, i. e., five repeated 
twice;+ while in D. cornigerus and D. sex-lobatus, now described 
for the first time, the whole number of radials is only five 
