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 ^Ye or more. Con- 

 struction of the ventral disk unknown. Column round; axial canal of 

 medium size. 



Horizon and Locality. — Hudson River group ; Cincinnati, 0. 



Remarks. — Glyptocrinus {Gaurocriniis) angularis Miller, and Reteocrinus 

 ^raa7/5 Wetherby, are undoubtedly synonyms o^ HdlY^ "Glyptocrinus'' par- 

 vus. Mr. Miller was good enough to send us two specimens, which he had 

 himself identified as " Gaurocrinus " angularis, and Mr. Yaupel kindly loaned 

 us the type of Reteocrinus gracilis. Both specimens are figured on Plate 

 XYIII., and a comparison of them with Hall's type of-' Glyptocrinus'' parvus 

 will prove that they all represent one species. 



HYPTIOCRINUS W. and Sp. 



(vTTTto?, bending back ; Kptvov, a lily). 



1892. W. and Sp.; Am. Geologist, Vol. X. (September), p. 138. 



Syn. Cyphocrinus S. A. Miller (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 ^yq, four of 

 them equal, angular at the upper end • the posterior one truncated by 

 the anal plate. Radials comparatively small, all heptagonal. Costals two. 

 Eixed 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 obhquely 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. Yentral disk depressed ; the posterior oral and the 



