294 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
always more or less excentric. Neither can the presence or absence of inter- 
distichals, unless accompanied by other distinctive characters, be considered 
sufficient for generic separation, as proposed in the case of Ctenocrinus 
Bronn.* Those plates are mere auxiliary pieces, which may be present 
or absent in the same species. 
Turbinocrinites Troost was proposed in MS., according to Hall,t for a 
species which was said to have the first anal plate on a level with the 
radials; but Troost’s typical species, Melocrinus Vernewili, had no such plate, 
or Hall could not have stated that the anal area was but slightly distinet 
from the other four. 
Cytocrinus was described by Roemer with three (?) basal plates — the 
exact number not having been ascertained. A good specimen in our collec- 
tion from Roemer’s typical locality plainly shows four plates, and we have 
no doubt the species is a Melocrinus. 
Phillipsocrinus MeCoy is described with four basals, sueceeded by seven 
plates in the next ring, which shows that it is an abnormal specimen. If it 
is, as we think, an Actinocrinoid, the abnormal seventh plate may haye 
necessitated the presence of a fourth basal. 
In addition to the species herein figured and described, we note the 
following : Melocrinus obpyramidalis Winchell and Marey, M. Vernewili Hall 
(not Oehlert). and JZ, nodosus Hall, which were described from unsatisfactory 
natural casts. Neither can MW. Pratten’ (Forbesioerinus Pratteni) McChesney, 
which was defined from a fragmentary specimen, or Melocrinus seulptus Hall, 
of which only the basal plates are known, or MW. brevidactylus Hall, which 
yas figured but not described, and the figure not properly published, be 
regarded as good species. 
* The genus Cfenocrinus was at first incorrectly defined. It was described by Bronn, 1840 (Jahrbuch, 
p. 542), with three basal plates, and this number was confirmed by Roemer (Lethaea Geogn., 1855, p. 251). 
Subsequently de Koninck considered the genus identical with Pradocrinus De Verneuil, which actually has 
three basals. Joh. Miller (Verhandl. naturh. Verein, 1855) admits more than three basals, probably five, 
and in 1857 (Neue Echinod. Eifl. Kalk., p. 255), asserts positively the presence of five basals. He com- 
pared Cfenocrinus with Glyptocrinus Hall, and supposed both to have ‘ parabasalia.” Schultze afterwards, in 
his Monograph, p. 63, proved from more perfect specimens that Cfenocrinus typus has but four basals, and no 
infrabasals, and referred that species to Melocriaus. Follman, in his article on the “ Unterdeyonischen 
Crinoideen,”’ Verhandl. Naturh. Verein, 1887 (private ed., p. 14), revised the genus Cfenocrinus with four 
basals, but pointed out no characters by which it may be distinguished from Melocrinus. 
¢ 28th Rep. N. Y. State Mus. Nat. Hist. (Museum edit.), p. 139. 
