BATOCRINID&. A473 
defined next to the margin of the plates, but are indistinct, or disappear 
altogether, in the middle portions. Color of specimens lighter than in the 
last species. The calyx up to the arm regions is obconical, wider than high, 
and a little convex at the sides. 
Basal cup short, projecting laterally, and forming a rim which is slightly 
excavated at the bottom. Radials somewhat shorter than those of <Aoro- 
crinus imaturus, the costals proportionally longer. The distichals vary in 
number; in the anterior ray there are 2X2 in the calyx, followed by 
free arm plates; the other rays have two in one division, but only one 
in the other, which is axillary and followed by palmars; exceptionally in 
the posterior rays the first is axillary in both divisions, but generally only 
that next to the anal side. Arms fourteen, rather stout, rounded on the 
back, and quite long; they are composed of two or three cuneate plates, 
which interlock and are followed by two series of transverse pieces, united 
by parallel sutures. Interbrachials six in three ranges; the first plate is 
large and extends to the top of the costals. There are three much smaller 
plates in the second range, and two in the third, the latter on a level with 
the arms. Anal area very wide, the first plate as large as the radials, the 
three succeeding plates fully equal in size to the single plate at the four 
regular sides, the middle plate being a little the largest. These plates are 
followed by numerous smaller ones, which take part in the ventral disk. 
Construction of the tegmen and position of the anus unknown. Of the 
column nearly three inches are preserved in one of the specimens ; it is de- 
cidedly tapering, the nodal joints high and projecting. So far as observed, 
the stem changes but little its general habitus. As it decreases downward 
in width, the internodal joints retain nearly the same proportions to the 
adjoining nodal ones as close to the calyx. 
Horizon and Locality. — Same as last. 
Types in the collection of Wachsmuth and Springer. 
Aorocrinus parvibasis W. and Sp. 
Plate XLV. Figs. 3a, b. 
1890. Dorycrinus parvibasis —W. and Sv.; Geol. Rep. Illinois, Vol. VIII., p. 177, Plate 17, Figs. 7 and 
9, 9a. 
1890. Dorycrinus parvibasis —S,. A. Mitimr; N. Amer. Geol. and Paleeont., p. 240. 
A small species. Calyx oblate-spheroidal, excavated at the bottom. 
Dorsal cup in form of a basin that rests upon the basals and portions of 
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