| 
ae 
HEX ACRINID ZA. 795 
the upper end than at the lower, and stouter in the middle than along the 
margins. The sockets in which they rest have not been observed, but must 
have been large, and probably extended to near the arm bases. Anus sub- 
central. Column round and small. 
florizon and Locality. — Kaskaskia group; Crittenden Co., Ky. 
Type in the Lyon collection. 
ftemarks. — Lyon described this species as having but one “ primary 
radial,” and two series of “secondary radials,” of which the first series is 
sald to consist of two, the other of four plates. He overlooked the small 
costal, and regarded the two succeeding rows, which are partly distichals 
and partly palmars, as “secondary radials.” He further supposed the wing- 
like appendages to be composed of three pieces; but the fact is that the 
suture lines indicated in his Figure 1b on Plate 3 are cracks in the specimen, 
and that plate evidently does not belong to this species. 
Pterotocrinus coronarius Lvov. 
Plate LXXIX. Figs. 7a, 6. 
1857. Asterocrinus (?) coronarius — Lyon ; Geol. Rep. Kentucky, Vol. III., p. 476, Plate 1, Figs. 1, la. 
1859. Pterotocrinus coronarius — Lyon and Cass., Syn. List Paleeoz. Echinod. (Proceed. Amer. Acad. 
Arts and Sci., Vol. IV., p. 802). 
1881. Péerotocrinus coronatus — W. and Spv.; Revision Paleocr., Part II., p. 91 (Proceed. Acad. Nat. Sci. 
Phila., p. 265). 
The structure of the dorsal cup is not known,* but the parts preserved 
are so characteristic of the genus, and again differ so essentially from the 
same parts of all other known species, that there can be no doubt that they 
belong to a distinct species. The tegmen is remarkable for the extravagance 
of its winged processes, which project out almost horizontally from the calyx, 
and form with it, as seen from above, a five-rayed petaloid star. The petals, 
viewed from above, are broad, narrowest at the extremities and slightly 
bending downward ; the margins of the upper face curve upward and form 
a well defined rim around the median portions. The appendages are massive 
* This species was described by Lyon from a single “unique crinoidal fragment,” having, as he said, 
“neither basal, radial, nor arm plates.” This is the type specimen which we have figured, and no other 
is known to have been discovered. Yet it is a singular fact that there is in the Museum of Comparative 
Zodlogy at Cambridge a lead cast of what seems to have been the same specimen, but having the missing 
dorsal portion of the calyx intact and showing all the characters of the genus. This cast is supposed to have 
been given to Professor L. Agassiz about 1850; but whether it was made from a partial restoration of the 
specimen which afterwards became Lyon’s type, or from another almost duplicate specimen, or whether the 
‘type was complete as originally found, and the dorsal cup broken off and lost before Lyon’s description was 
made, can only be conjectured. 
