Camerate Crinoids. — Wachsmuth and Springer. 141 
top of the dorsal cup; the hight of the cup 11 millim.,thatof the ven- 
tral disk 16 millim., and the length of the partition walls 8 millim. 
Dorsal cup broadly truncated at the base ; the sides almost straight, 
gradually expanding upwards. The radials and costals at their sur- 
faces sharply keel-shaped, especiall}' the former, and the angu- 
larity continued upon the distichals, but not attaining the prom- 
inence as on the plates below; the first interbrachials slightly 
convex, with a small tubercle in the center. 
Basals small and nearly of the same size, forming a concavity, 
which is rather small and shallow for the genus. Radials near 
the upper end fully as wide as long, and twice as wide as at the 
lower part, which curves gently inward to meet the basals. First 
costals twice as wide as high; the second, which is higher and 
wider, rarely truncated by the interdistichals. First distichals 
twice as large as the second, and but little smaller than the ax- 
illary costals. The palmars small and pentangular. First inter- 
brachials longer than wide, a little smaller than the radials ; the 
upper two together nearly twice as wide as the first, their 
upper ends rising to the hight of the second or third arm 
plates. Interdistichals but little smaller than the upper inter- 
brachials, and protruding upwards in a similar manner. Ven- 
tral disk conical, its sides convex. The ten plates which rest 
upon the interbrachials and interdistichals, respectively, and form 
the compartments for the reception of a pair of arms, are twice 
as high as the intervening ones, which rest against the sloping 
upper faces of the palmars. There are in all twenty partitions 
around the disk, and each arm occupies a separate compartment. 
The partition walls are moderately thick, and slightly grooved at 
their outer faces. The ten larger ones rise to a level with the 
upper end of the first ring of plates in the disk, of which they 
form wing-like extensions; they are sabre-shaped, and pointed at 
their ends. The second ring of the disk consists of four plates, 
which are much narrower at the top than at the bottom, and 
two of them are narrower than the others. The construction 
of the anal tube, its length, and the structure of the arms not 
known. 
Horizon and Locality: Niagara group, St. Paul, Ind. 
Type in the collection of Wachsmuth and Spi'inger. 
