322 THE CEINOIDEA CAMEEATA OF KOETH AMEEICA. 



Orals large ; the posterior one small and lunate^ owing to the almost central 

 position of the large anal tube. 



Horizon and Locality, — Upper Helderberg ; Clark Co.^ Ind. 



Types in the collection of Victor W. Lyon. 



Bemarks. — Differing from all other known species of this genus in the 

 great size of the calyx, the form and depth of the basal pit, in having two 

 secondary interbrachials, and in the number of the slits. The specimen on 

 Plate XXYI., Fig. 7, exhibiting the inner floor of the disk, is very interest- 

 ing as showing the communication of the slits with the inner cavity. 



Dolatocrinus major W. and Sp. (nov. spec). 

 FlateXXV.Fi^.S. 



A very large species, in general form resembling the preceding, but with 

 a shallow basal depression, four arms to the ray, and without surface orna- 

 mentation. Dorsal cup depressed-bowl-shaped, almost three times as wide as 

 high, flattened below ; the radials and part of the costals stretched out hori- 

 zontally ; the basals forming a shallow concavity surrounded by a thickened 

 rim ; the sides gently bending upwards and becoming parallel at the top of 

 the first distichals. The plates are smooth, with the exception of a small 

 rounded node upon the two costals ; that of the first costal occupying the 

 upper end of the plate, that of the second the median part. Radials compar- 

 atively small, considerably wider than long; the upper and lower lateral 

 faces almost equal ; the lower margin thickened and forming a rim around 

 the basal concavity. First costal as large as the radials ; the upper face 

 decidedly convex, and the lateral ones slightly, but the lower face straight. 

 Second costal larger than the first, broadly pentangular. Distichals 1 X 10 ; 

 large; axillary; supporting two good sized fixed palmars, and these the 

 free arms. Arms twenty, arranged at almost equal distances around the 

 calyx. Interbrachial spaces somewhat depressed at their lower ends, and 

 slightly receding between the arm bases ; the first plate large, its upper half 

 considerably wider than the lower half, its upper face truncate and somewhat 

 concave. The plate of the second row is approximately as large as the first 

 costals, but higher than wide and hexagonal ; the lower lateral faces parallel, 

 the upper lateral ones sloping. There are three plates in the third row, and 

 others above. Interdistichals one. Structure of the ventral disk unknown. 



Horizon and Locality, — Upper Helderberg group ; Falls of the Ohio. 



Type in the collection of Victor W. Lyon. 



