Description of New Genera of Echinodermata. 21 
eight or nine, the first rests between the upper sloping sides of two 
basal plates and is in line with the first radials; it is followed by 
three plates in the second series, and in one specimen three plates 
in the third series and in another four; these are followed by a 
single plate projecting an angle up between the under sloping 
sides of tertiary radials; the vault and proboscis are constructed of 
highly tumid polygonal plates; the proboscis extends as far as or 
beyond the arms; column round. 
This is a handsome little species, distinguished by its sixteen 
arms and the structure of the calyx from all others. 
Found in the Keokuk Group at Crawfordsville, Indiana, and 
now in the collection of Wm. F. E. Gurley. 
DICHOCRINUS CINCTUS, Nn. Sp. 
Flate IV., Fig. 10, symmetrical side view; Fig. 11, azygous side, show- 
img vault and valvular opening ; Fig. 12, summit view. 
Calyx obconoidal, nearly twice as high as wide, somewhat trun- 
cated at the arm bases, except upon the azygous side, surface of 
the plates bearing a collection of fine longitudinal lines from the 
rim at the base, over the central part of the first radials, to the first 
rim plates, with fine transverse lines between, especially near the 
top of the calyx; sutures not impressed, and the transverse and 
longitudinal lines cross without interruption ; the band or rim at 
the base suggests the specific name. The two basals form a little 
cup, the height of which is equal to the greatest diameter; they are 
contracted above the base so as to leave a small, smooth, half 
cylindrical rim or band at the bottom of the cup; the first radials 
are about twice as long as wide, very gradually increase in width 
to the upper truncated end, which bears a concave facet, a little 
more than one-third the width of the plate, for the attachment of 
the second radial or first brachial piece; second radial thin, 
rounded; the third radial a little thicker, rounded, and bearing 
upon its upper sloping sides the free arms; arms ten, long, rounded 
externally, composed of a single series of thin plates, bearing long, 
strong pinnules closely packed together. 
Regular interradials forming part of the vault, and standing but 
very little above the upper truncated edge of the first radials ; first 
azygous interradial as large as the first radials, inflected toward the 
