BATOCRINIDZ&. 377 
The smallest known species of Batocrinus. Height of crown not exceed- 
ing 38cm. Calyx about as wide as high, the arm bases projecting. Dorsal 
cup obconical; sides straight from the bottom to the top of the distichals, 
thence curving more abruptly outward; base broadly truncate. Plates 
slightly convex, without ornamentation; suture lines depressed. Color of 
specimens lighter than that of Rhodocrinus Kirbyi and Dichocrinus inornatus 
from the same locality. 
Basals short, forming a broad hexagonal disk, which is but very little 
excavated at the bottom. Radials considerably wider than long ; their upper 
faces concave. Costals small, quadrangular and pentangular; the first con- 
vex below, more than twice as wide as long; the second not longer than the 
first but wider. Distichals 2 x 10; followed by two rows of cuneate palmars, 
which support the free arms. Arms twenty, comparatively heavy, rounded 
on the back, the tips slightly incurved and somewhat flattened. Inter- 
brachials three, sometimes with a small one on top; the first extending 
to the full length of the first distichals, those of the second range arched 
over by the palmars, except at the posterior side where a narrow piece 
intervenes between them. The anal plate is followed by three rather 
large pieces, and these by two and one. The ventral disk is a little lower 
than the dorsal cup, highly convex, and slightly depressed at the interradial 
and interdistichal spaces; the ambulacra elevated, and covered by several 
nodose plates of a first and second order. The interambulacral spaces are 
paved by numerous very small, convex pieces. Orals comparatively small. 
Anal tube slender, shorter than usual in this genus, extending but little 
above the tips of the arms. Column short, the nodal joints in the upper 
part large, rounded at their edges; the intervening joints comparatively 
short and narrow, contrasting strongly with the nodal ones. Toward the 
lower end the joints are more uniform. The column has been observed by 
us to its full length in several specimens, in none of which it measures 
more than six inches. It generally tapers to its distal end, where it termi- 
nates in a sharp point. The lower part, to about one third of its whole 
length, bears short lateral cirri, which are arranged singly — not in whorls. 
Horizon and Locality.— Kinderhook group; Le Grand, Marshall Co., 
Towa. 
Types in the collection of Wachsmuth and Springer. 
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