ECHINODERMATA OF THE BRASSFIELD FORMATION 
17 
again. A part of another arm forms the right side of the frag- 
ment; the distichals of the left branch are followed by two arm 
branches, of which the left one has nine palmars, and the right 
one has five palmars. In the case of each arm, the two median 
arm branches following the distichals are broader and shorter; 
the two exterior arm branches of the same set are narrower and 
longer, recalling in this respect CUdochirus of which it may be 
another species. 
Clidochirus ulrichi sp. nov. 
Plate II, figs. 1 A, B; text figure 1 
Infrabasals three, 1.3 mm. in height, exposed surface sloping 
at the same angle as the basals. Basals, 2.5 mm. in height. 
Radials, except in the case of the right posterior arm, 2 mm. in 
height. Radials, except in the case of the right posterior arm, 
followed by two costals, of which the first has a height of 1.7 mm. 
while the second or axillary costal has a height of about 2 mm. 
at its middle. The right posterior arm appears to consist of a 
radial followed by three costals, and the designations first, 
second, and third or axillary costal are used in connection with 
this arm in the immediately following parts of this description. 
The radianal is relatively long and narrow, narrowing especially 
toward the base; it lines the left margin of the radial at the base 
of the right posterior arm for its entire length and borders also 
on the lower left margin of the first costal of this arm. The 
anal x plate borders on the lower left margin of the second costal 
and lines the left margin of the first costal of the right posterior 
arm; on its left side it barely reaches the lower right corner of 
the second or axillary costal, but borders on the right side of 
both the first costal and the radial. In all arms there are four 
distichals in each vertical series. Each arm terminates with 
four series of palmars, of which, in the specimen at hand, the 
two outer series consist of about eleven or twelve palmars, while 
the two inner series appear to be shorter and to consist of only 
eight or nine palmars. 
