136 
SMITHSONIAN INSTITUTION 
angular at the back, branching but few times. It is based on a single specimen 
from a higher horizon than those following, and I have been able to expose the 
crown fully for both lateral and dorsal views. 
Horizon and locality. Louisville limestone; Jetferson County, Kentucky. 
Gissocrinus delicatus new species 
Plate 32, fig. 2 
A small species, of the type of G. typus Bather, Crin. Goth, p. 155, but 
with cup more slender and turbinate, and arms more delicate with numerous 
bifurcations. IBB apparently 3, followed by very elongate BB. Anal tube ex- 
tremely long, projecting beyond the tips of the arms. There is only the one 
specimen, very well preserved. 
Horizon and locality. Beech River formation ; Decatur County, Tennessee. 
Gissocrinus magnibrachiatus new species 
Plate 32, figs. 3-6 
Of very large size, far larger than any other known species ; crown so far 
as preserved about 75 mm. high. Calyx small, crushed in the only specimen 
preserving it and its composition unknown. Arms of relatively enormous size 
compared with the calyx, composed of long, broad, low convex and very thin 
brachials with smooth surface, ranging from 10 to 14 mm. high to 7 to 10 mm. 
wide, with frequent bifurcations in the lower part, even from successive bra- 
chials; articulating faces of brachials connected by i, 2, or occasionally 3 small 
patelloid plates, most frequently 2 in succession, arising from deeply curved 
facets occupying less than half the width of the brachial; the distal faces of the 
axillaries have 2 pairs of patelloid plates abreast and near the lateral margins, 
while on the other faces the patelloid is in the middle; they are as thick as the 
brachials, and pass through to the inside. The positions of these connecting 
plates coincide exactly with the course of the ventral furrows or food grooves 
on the inner side of the brachials, which branch upon the axillaries and are 
doubled at the distal end; the grooves are extremely narrow, not over one fifth 
the total width of the brachial, and are closed by a double row of small, alter- 
nating covering plates not over half a millemeter long and wide. 
Having assembled an excellent series of specimens of the principal English species, the 
study of these in connection with Bather’s exhaustive illustrations of the Swedish forms gave 
me a mental picture of this as a genus of wide variations, especially in the arms, under which 
the unexpected was always liable to occur. With this in mind, when the first specimens of 
this extraordinary form were disclosed among the Tennessee collections, I labeled them 
Gissocrinus without any very definite reason for it. As other specimens appeared showing 
complete constancy of characters hitherto without precedent, I began to wish for assistance 
toward the understanding of it, and accordingly sent a photograph of one of the most instruc- 
