A Nezv Cystocri)ioidean Species. — Sardeso?i. 275 
to the one in hand, except that there is no evidence that the 
canals or grooves open to the exterior except on weathered 
specimens. There may be a "dorsocentral plate" not here well 
observed. The 'rami' do not separate, but fuse laterally. In 
general form this root is even more like the "dorsocentral'' 
of the Antedon larva than is that of Glyptocrinus, and, there- 
fore, somewhat strengthens the comparison of these as made 
by Wachsmuth and Springer, op. cit., although the large size 
in this case indicates that the structure was not merely larval. 
In structure, the root as a whole resembles also such sup- 
posed Cystoidea as Lichenocrinus, and involves that genus in 
the general morphological comparison. On one side of one 
of the specimens, as already described, the intercalation of 
radiating rows of plates is so closely consecutive that the ap- 
pearance of rows changes to that of distributed arrangement, 
and then there is a sti iking likeness to Lichenocrinus. The 
structure of radiating canals beneath the covering plates, with 
a furrowed "centrodorsal" plate or layer beneath these in turn, 
and a central opening leading into a long pentagonal stem 
composed of circles or sections of five plates each, describes 
quite evidently both Lichenocrinus and our crinoid root. In 
the latter the greater size and more numerous plates usually 
arranged in rows form rather a generic distinction than a 
discrepancy. ' 
The root of crinoids appears to be the counterpart of the 
calyx in type of symmetry. If this is true of Lichenocrinus, 
then the body to which its stem attached would be rather a 
cystid than a crinoid, as indicated by the dispersed arrange- 
ment of the plates. Lichenocrinus is common in the Galena 
(Trenton) stage of Minnesota, associated with innumerable 
crinoid and cystid stems of several types, to which in main 
no calyx is associated among collected fossils. Evidence here 
admits that Lichenocrinus might be the larval anchor of some 
one of very different types of Echinoderms. This possibility 
recalls the ver\- striking well known relation of not only Cri- 
noidea to Cystocrinoidea, but also Asteroidea and Echinoidea 
to sessile and stalked Cystasteroidea and Cystechinoidea, and 
mav open to speculative consideration the question whether 
even Asteroidea and Echinoidea of the Ordovician time did 
not pass through a stalked larval stage and metamorphosis. 
