192 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
founded. Through the kindness of Prof. Whitfield we were permitted to 
examine this specimen, and to free it from the surrounding matrix, when we 
found the pinnules well developed, and the plates of the calyx arranged as 
in the typical form of Thysanocrinus (Plate XVII. Fig. 4). 
Eucrinus was separated from Z/ysanocrinus on account of having twenty 
arms, as against ten in the latter. A bifurcation or two, more or less, cannot 
be regarded as a good generic distinction, and we therefore place Angelin’s 
species: Eucrinus interradialis, E. levis, E. ornatus, EB. quinquangularis and 
E.. speciosus, under Thysanocrinus ; but not his £. nuinor or EL. venustus, which 
are types of a different genus. Rhodocrinus quinquelobus Schultze, which we 
formerly placed under Lucrinus, is a Rhodocrinoid. Thysanocrinus (Rhodo- 
crinus) microbasilis, and Th. (Rhodocrinus) pyriformis Billings, have been re- 
ferred by us to Archwocrinus ; Th. immaturus to Idiocrinus. Thysanocrinus 
aculeatus and Th. canaliculatus are named from arm fragments. Dimerocrinus 
oligoptilis, and its synonym JD. aptilis from Russia, belong to Tazocrinus. 
Glyptaster pentangularis Hall is described from internal casts, and is, to say 
the least, a doubtful species. Cyathocrinus waldronensis 8. A. Miller (Dimero- 
crinus waldronensis W. and Sp.) cannot be identified from the description and 
fizure, but may be a young Thysanocrinus inornatus. Neither can Glyptaster 
Egani 8. A. Miller, which is described from a fragmentary specimen. 
Thysanocrinus liliiformis Hatt. 
Plate XVIII. Fig. 4. 
1852. Thysanocrinus liliiformis —Ha; Paleont. N. York, Vol. I1., p. 188, Figs. la—/- 
1881. Dimerocrinus liliiformis — W. and Spv.; Revision Palxocr., Part I]., p. 199, and Proceed. Acad. Nat. 
Sci. Phila., p. 373. 
1889. Thysanocrinus liliiformis —S. A. Miter; N. Amer. Geol. and Palont., p. 286. 
Form of calyx apparently globose (the exact shape cannot be ascertained 
owing to the somewhat crushed condition of the type specimen); the plates 
ornamented by elongate nodes or interrupted strize, which give to the surface 
a corrugated appearance. 
Infrabasals small, scarcely visible in a side view. Basals nearly as large 
as the radials; that of the anal side even larger and broadly truncate, the 
others angular above. All plates in a radial direction provided with a low, 
almost flat, obscure ridge, following the median line of the plates, and 
covered by longitudinal striae which are continued into the arms. Radials 
wider than long, but slightly angular below; their lateral faces short, leaving 
