84 Cincinnati Society of Natural History. 
truncated above, the sloping inferior sides resting between the basals. 
The lowest point of these plates, which is on a line with the suture 
joining the basals, is slightly excavated, giving the lower end a bifur- 
cate appearance. The interradial sides are depressed, leaving an ele- 
vated central ridge to this part of the ray which is thus continued 
throughout the radial and brachial series. 
Second radials—Five, quadrangular, higher than wide, equal in size, 
squarely truncated above and below, lateral margins depressed. 
Third radiais—Five, pentagonal, higher than wide, wider above, 
with two articulating surfaces upon which the rays divide. Lateral 
edges depressed into the borders of the interradial spaces, upper mar- 
gin slightly excavated between the articulating faces, giving the plate 
a bifurcate appearance. 
Brachials—First series, ten, quadrangular, higher than wide, equal 
in size, and alike in form. Second series, ten, pentagonal, higher than 
wide, wider above, with two articular facets, upon each of which an arm 
originates, a slight excavation occupying the space between these 
facets. 
Arms—Twenty, long, slender, composed of equal, quadrangular 
plates, about as high as wide, without bifurcation or divisions. . 
Pinnule—Long, delicate, and originating on alternate arm plates 
either side of the ambulacral groove. 
Vault—Unknown. 
Anal and interradial spaces filled by an indefinite number of small, 
delicate, generally hexagonal plates. Among these may be detected 
those of the “fixed pinnule,” to which I called attention in my de- 
scription of Reteocrinus richardsoni. 
I have great pleasure in again acknowledging the bigh character of 
the work done by Mr. Billings, whose keen discrimination detected the 
generic value of the imperfectly preserved specimens with which he 
had to deal. This beautiful fossil was discovered in Lime Kiln Hol- 
low, formerly a noted collecting ground, by Ernst H. Vaupel and 
Mr. John Nickles, to whose kindness I owe this opportunity of de- 
scribing it. 
Nore oN THE TRENTON Fossits oF MERCER Co., Ky. 
Since publishing my article on the Trenton Limestone of Kentucky 
(this JournaL, July, 1880), I have discovered many rare additional 
forms. Among them must be noted a large species of Comarocystites; 
