Dyipe THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
a lateral projection, or sort of elongate node, which stands obliquely up- 
ward, and gives to the lower part of the arms a zigzag outline. The 
succeeding plates are biserial, and of these the three or four lower ones 
are considerably higher than those above. The upper margins of the arm 
pieces project slightly over the lower margins of the succeeding ones, the eg 
sides are serrated, and the lines of union between them somewhat waving. 
The three or four proximal pinnule joints are provided with moderately long 
hooks. Regular interbrachials : 1, 2, 2; the first very large, rising to the 
middle of the second costals, the two of the upper row quite minute. Anal 
plate as long as, but narrower than the radials, followed by 2, 3, and 3 pieces. 
Interdistichals one. The grooves between the rays extend up almost verti- 
cally to one half the height of the tegmen, and are paved by rather large, 
flat pieces; while the orals and ambulacral plates are spiniform. Orals 
pushed out far to the anterior side; they are comparatively small and in 
close contact ; the ambulacral plates arranged in alternate rows. Anal tube 
nearly central, moderately large, and composed of spinous plates. 
Forizon and Locality. — Lower Burlington limestone ; Burlington, Iowa, , 
Sedalia, Mo., and Lake Valley, New Mexico. | 
Actinocrinus gracilis W. and Sp. (nov. spec.). , 
iotemn 1. 1g. 1. 
ee 
Approaching 4. tenwisculptus, but a smaller species, and having a much 
larger number of arms; also the ornamentation of the plates more obscure. 
Dorsal cup bowl-shaped, the sides to the top of the distichals slightly convex, 
then bending abruptly outward ; the plates a little tumid, covered by faint 
radiating striz and well defined ridges, the latter following the rays, and 
forming deep depressions at the interdistichal spaces. 
Basals small, with a slightly projecting rim. Radials one third larger 
than the costals, and both wider than long. Distichals 2X 10. Three bifur- | 
cations occur in the calyx, and one or two in the arms, all taking place from 
the second plate, and all above the first axillary from one side only, the oppo- 
site sides giving off a free arm. Arms from eight to ten to the ray, quite 
slender, a little wider at the upper end than at the lower; the three or four 
proximal plates of each arm long and cuneate, and their widest sides, toward | 
the upper end, provided with a short lateral node, which gives to the lower | 
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