200 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
the first or second palmar; composed of wedgeshaped joints, which are as 
long as wide, and rounded on the back. Pinnules stout, well separated. 
Interbrachial spaces depressed, flat; the first plate of the regular sides as 
large as the costals; followed by two plates in the second row, and a number 
of others, which, though well defined, are more or less irregular in their 
arrangement. Anal side wider, divided by a longitudinal row of hexagonal 
plates; the plates at each side of this row about as numerous as the whole 
series of plates of the four regular sides. Interaxillaries five or more. Con- 
struction of the ventral disk unknown. Column round; axial canal of 
medium size. 
Horizon and Locality. — Hudson River group ; Cincinnati, O. 
Remarks. — Glyptocrinus (Gaurocrinus) angularis Miller, and Reteocrinus 
gracilis Wetherby, are undoubtedly synonyms of Hall's “Glyptocrinus” par- 
vus. Mr. Miller was good enough to send us two specimens, which he had 
himself identified as “ Gaurocrinus” angularis, and Mr. Vaupel kindly loaned 
us the type of Reteocrinus gracilis. Both specimens are figured on Plate 
XVIII., and a comparison of them with Hall’s type of ‘‘ Glyptocrinus” parvus 
will prove that they all represent one species. 
HYPTIOCRINUS W. and Sp. 
(trrvos, bending back ; Kptvov, a lily). 
1892. W.and Sp.; Am. Geologist, Vol. X. (September), p. 188. 
Syn. Cyphocrinus 8. A. Mirier (October 26, 1892); Adv. Sheets, 18th Rep. Geol. Surv. Indiana, 
p- 56. 
Name referring to the character of the arms, which hang downward. 
Calyx depressed, wheel-shaped. Infrabasals five, small. Basals five, four of 
them equal, angular at the upper end; the posterior one truncated by 
the anal plate. Radials comparatively small, all heptagonal. Costals two. 
Fixed brachials rather large, except the first costals, which are quite short, 
and quadrangular. Distichals one, the distal face broadly truncated; fol- 
lowed by several sharply cuneate pieces, which interlock, and of which the 
two or three proximal ones (in the type) take part in the calyx. Arms 
stout, probably biserial, and pendent, to judge from the arm openings, which 
are directed obliquely downward. First interbrachials of the regular sides 
very large, succeeded by several rows of smaller pieces. Anal plate touching 
the basals and rising above the radials; supporting three much smaller 
plates and others above. Ventral disk depressed ; the posterior oral and the 
