Description of New Genera of Echinodermata. 13 
unequal. The superior edge is nearly straight and rounded The 
articular facet is very broad, nearly horizontal, and furnished with 
a prominent transverse ridge, which is situated nearest the exter- 
nal margin. Exterior to this is a small ridge which coalesces with 
the main one before reaching the extremity of the pieces. Both 
ridges are strongly crenulated 
‘* Anal pieces—Of these pieces only one remains in the specimens 
before us. It is rather small, elongate hexagonal, and is wedged 
in between two of the first radials, above which it projects about 
half its length. 
‘*The secondary radials, vault, arms and column are unknown. 
‘« Dimensions.—Height of calyx, .30; width, .go; height of first 
radial pieces, .26; width of same, .42.” 
His specimens were from Hinkston Creek, Boone County, and 
on the Missouri River near Lexington, while our specimens are from 
Kansas City in the same vicinity. His definition is complete, as 
far as it goes, and we may add only that which our specimens dis- 
close in addition. 
The column is round and composed of alternately thicker and 
thinner plates radiately furrowed near the outer circumference of 
the articulating faces; the second radial or brachial articulates 
upon the crenated ridge on the top of the first radial, bears a tuoth- 
like process that enters the socket in the middle of the posterior 
part of the first radial, and lateral processes that fill the furrows at 
the uniting joints of the first radials, and bears a strong spine, 
externally, that is directed upward at an angle of about forty-five 
degrees; the plates bear upon their upper inner sides the free arms; 
arms ten, the first plate articulates upon a serrated edge of the second 
radial, the next plate is wide and thin, and above this the arm con- 
sists of a double series of thick interlocking plates that make coarse 
wide arms, depressed convex externally, and flattened upon the 
sides almost as if cut by a knife so as to close up tight like an 
Encrinus; the first azygous plate is truncated and subquadrate upon 
the upper face which is serrated near the outer margin for the 
articulation of the second plate; beyond this the vault is unknown. 
