MELOCRINID^. 319 



Dolatocrinus liratus (Hall). 

 Plate XXVI. Fig. S. 



1863. Cacabocrinus liratus — Hall ; 15th Rep. N. Y. State Cab. Nat. Hist., p. 139. 

 1881. Dolatocrinus liratus — W. and Sp. ; Revision Palseocr., Part II., p. 126. 



Syn. Cacabocrinus liratus, var. multilira — Hall; 15th Rep. N. Y. State Cab. Nat. Hist., p. 139. 



Yery closely resembling D. glyptus^ and probably a mere variety of that 

 species. The specimens referred to the latter by Hall are shorter and their 

 basal portions more depressed, but this may possibly be due to pressure. 

 They agree in the form and arrangement of the plates, and both have two 

 primary arms to the ray, a depressed ventral disk, ridges along the ambu- 

 lacra, and an almost central anal tube. The only perceptible difference is in 

 the style of ornamentation. The ridges, which in D. glyptus are more or 

 less interrupted, are continuous in D. liratus. It has, besides, large ridges 

 radiating from the centre of the plates to each of their angles, and three to 

 five smaller ridges passing out to the sides, where they join with similar 

 ridges from adjacent plates. The plates of the ventral disk are densely 

 crowded with large and small prominences, similar to those found in certain 

 species of Amplioracrinus. 



Horizon and Locality/. — The same as the preceding species. 



Type in the New^ York State Cabinet of Natural History at Albany. ' 



Dolatocrinus icosidactylus W. and Sp. (no v. spec). 

 Plate XXVI. Figs. 5a-d. 



A large and greatly depressed species of the type of D. glyptus^ but 

 readily distinguished by having four instead of two primary arms to the ray. 

 When not crushed, the calyx to the base of the anal tube only about four 

 fifths as high as wide, but it appears to be still shorter in the usual preserva- 

 tion. Dorsal cup twice as high as the tegmen, broadly cup-shaped, flattened 

 to the top of the costals, and the basals formed into a funnel-shaped cavity, 

 surrounded by a circular ridge. The median lines along the plates of the 

 rays to the bases of the arms elevated into prominent ridges, and the middle 

 of each radial and costal crowned by a small central node. The nodes are 

 directed longitudinally ; they are in some specimens quite conspicuous, while 

 the ridges are almost obsolete ; in others, however, the ridges are almost as 

 high as the nodes. Smaller ridges, or more properly speaking, rows of elon- 



