72 Cincinnati Society of Natural History. 
| 
Arms, ten; pinnule, long, quite in contact, and some of the lower 
ones appearing to become incorporated into.the body or cup; column, 
quadrangular. ; 
XENOCRINUS PENICILLUS, Nl. Sp. 
Plate I., fig. 3, natural size, showing azygous side; fig. 3a, same specimen magnified two 
diameters; fig. 3b, magnified view of the azygous side of a compressed specimen; fig. 3c, view _ 
a the posterior side of a specimen, showing the arms and pinnulx, magnified about half its 
iameter. 
Basals.—Basals, four, uniting at the angles of the column, about 
twice as wide as high, two of them are hexagonal and the other two 
pentagonal. The surface is granulous. 
Primary radials.—Primary radials, three, in each series, about fies 
as long as wide; each series forming a convex, elevated ridge, con- 
tracted at the point of the union of the plates; four of the series are 
supported in the angles, formed at the junction of the basal plates, and 
the fifth or posterior series is supported upon the middle of the basal 
plate opposite the azygous side. The plates have about the same 
length. The third-primary radials are a little wider in the upper part 
than the others, and support upon the two superior sides the secondary 
radial series. | 
| Secondary radials.—The secondary radial or brachial series is con- 
tinued into the free arms, the first plate has a length about equal to 
that of a primary radial, the second plate is a little shorter, the third 
plate about two thirds as long, the fourth plate about half the length, 
or a little wider than high, the fifth plate about one third the length, 
and the sixth plate has a length about equal to one half its width. 
- Above this the plates become shorter, without any noticeable contrac- 
tion of the width, until the arms are wholly free from the vault, the 
plates are then cuneiform, and the width is equal to the length of about 
three plates. . 
‘Interradial and inter-secondary radial spaces.—These long, narrow, 
depressed areas are covered with small plates, having a tubercle or 
short spine in the central part of each. There are more than seventy- 
five plates in each interradial area, and twenty-five or more in each in- 
ter secondary radial area before reaching the top of the cup, but the 
small plates continue over the margin of the vault, and undoubtedly 
cover it, and also more or less of the long proboscis, which is extended 
from the anterior or azygous side. 
Azygous area.—The azygous area is remarkably large, and covered, 
in the central part, by a vertical series of plates having about the same 
size as the regular radial series; and upon each side of the vertical 
series, there is a ‘depressed area covered by small plates, having a 
