606 THE CRINOIDEA CAMEEATA OF KOETH AMERICA. 



Cactocrinus reticulatus, var. ovatus (Hall). 

 PlateLVn.Fig.il. 



1861, Actinocrinus ovaius — Hall; Descrip. Ke'n' Paleeoz. Crin., p. 10. 



This form scarcely deserves the rank of variety. It differs from C. reti- 

 culatus in the more rounded form of the dorsal cup, and the less expansion of 

 the arm bases ; in the more depressed form of the ventral disk, its shorter 

 spines, and in the ornamentation of the dorsal cup. The radials and cos- 

 tals are traversed by three parallel ridges, which pass into the basals, and 

 generally terminate in denticulate nodes at their lower margins ; the ridges 

 between the interbrachials of first and second order, and toward radials and 

 costals being double, all others single. 



Horizon and Locality. — Same as last. 



Cactocrinus denticulatus w. and Sp. (nov. spec). 

 Plate LYII. Figs. 5a, h. 



Calyx of medium size, abruptly spreading above the distichals; the sur- 

 face ornamented by radiating ridges and nodes similar to those of C. reticu- 

 latus ; the arms covered profusely with tooth-like projections. 



Basals of moderate size, their lower margins projecting beyond the sides 

 of the column. Radials as large as both costals together, wider than long, 

 and covered with a conspicuous transverse node, from which the ridges pass 

 out to all sides, there being three ridges to the basals and costals, and one to 

 each interbrachial. First costals hexangular, smaller than the second, the 

 latter heptangular. Distichals a little smaller than the costals. Palmars 

 short, and narrower than the breadth of the arms ; three of each ray trun- 

 cated, giving off simple arms, the fourth axillary and followed by post- 

 palmars. Arms crowded and their bases bending outward ; normally five to 

 the ray ; long, very heavy, infolding, and of uniform thickness throughout, 

 but flattening toward the extremities. They are composed from the second 

 joint lip of two series of moderately long, convex pieces, which are sur- 

 mounted by two sharp elongate nodes. The nodes increase in length up- 

 ward, arranged in longitudinal rows ; two of them running along the sides 

 of the arms, and the others along the middle, on each side of the median 

 suture line, giving to the arms a somewhat angular outline. Pinnules pro- 



