268 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
1881. W.and Sp.; Revision Paleoer., Part IT., p. 185 (Proceed. Acad. Nat. Sci. Phila., p. 359). 
1883. W.and Sp.; Amer. Journ. Sci., Vol. XXV., pp. 255 to 268. 
1883. S.A. Minter; Amer. Journ. Sci., Vol. XXVI., pp. 105 to 113 ; and Cincin. Soe. Nat. Hist., Vol., 
VI., pp. 220 to 228. 
1885. W. and Sp.; Revision Paleocr., Part IIT., p. 102 (Proceed. Acad. Nat. Sci. Phila., p. 324). 
1859. S. A. Micrer; North Amer. Geol. and Paleont., p. 247. ; 
Not Glyptocrinus D’OrxicNy, 1852; Cours élément. de Paléont., Vol. II., p. 142, nor Prodréme, 
Vol. L., p. 47. 
Not Glyptocrinus Hatt, 1863, Trans. Albany Inst., Vol. IV., p. 202; nor 28th Rep. N. Y. State 
Mas., p. 132 = Mariacrinus. 
Not Glyptocrinus Hatt, 1872; 24th Rep. N. Y. State Cab. Nat. Hist., p. 206 = Reteocrinus. 
Not Glyptocrinus Haut, 1872; ibid., p. 207 = Plychocrinus. 
Not Glyptocrinus WetuERBy ; Journ. Cincin. Soc. Nat. Hist., Vol. IV., p. 88 = Reteocrinus. 
Not Glyptocrinus S. A. Mitten; ibid., Vol IV., p. 74 = Compsocrinus, nor p. 75 = Reteocrinus. 
Not Glyptocrinus Ernerrce and Nicworson, 1880, Silur. Foss. of Girvan Distr., p. 328- 
Syn. Fossil Encrinite ANTHONY, 1838; Amer. Journ. Sci., Vol. XXXV., p. 405. 
Syn. Icosidactylocrinites OwEN, 1843 (Catalogue name). 
Syn. Pycnocrinus 8. A. Mixer; Journ. Cincin. Soc. Nat. Hist., Vol. VI., p. 231. 
Calyx obconical or subglobose; plates thin, often highly ornamented; the 
fixed brachials passing imperceptibly into arm plates, and the interbrachials 
into disk plates; the arms rising vertically from the edge of the tegmen. 
Basals five, of uniform size, forming a small cup. Radials and costals of 
nearly equal size; the second costal hexagonal. Distichals varying in num- 
ber, there being but two in species in which palmars take part in the calyx; 
but when the second bifurcation takes place in the free arms, they are quite 
numerous, frequently six to eight or more in the calyx, followed by several 
others in the free arms. When this is the case, the second distichal gives 
off a large pinnule; while in the other the proximal pinnule is developed 
into an arm. Arms rarely branching beyond the second bifurcation, rising 
vertically from the calyx; they are long, slender, rounded on the back, 
and composed of a single series of short, slightly wedge-shaped pieces, 
which do not interlock. Pinnules slender, closely arranged; the proximal 
ones the stoutest, and frequently incorporated into the calyx. 
Interbrachials definitely arranged; the first large, resting upon the slop- 
ing upper faces of the radials; there being two plates in the second row, and 
two, sometimes three, in the higher ones. The anal side widest, having 
generally three plates in the second and all succeeding rows. Interdistichal 
spaces large, composed of numerous small plates; some species also have 
interpalmars. Ventral disk depressed-hemispherical, very slightly extend- 
ing above the level of the arm bases; the ambulacra subtegminal, except 
near the periphery, where some of the small covering pieces are exposed, 
but the course of the ambulacra is indicated by surface ridges. Plates 
of the disk very minute and irregularly arranged, decreasing in size toward 
