MELOCRINID^. 303 



as wide. Distichals two, the two divisions separated by one or two inter- 

 distichals. Palrnars apparently not united laterally, and there may have 

 been two appendages to each ray. Interradial spaces depressed in the upper 

 portions ; arranged : 1, 2, 3, with numerous plates above, which connect 

 with others in the disk. Anal area somewhat the widest, and with three 

 plates in the second row. Ventral disk almost flat ; composed of very uni- 

 form, slightly convex pieces. Anus excentric, probably without a tube. 



Horizon and Locality. — Niagara group; Waldron and Hartsville, Ind. 



Ti/2oe in the American Museum of Natural History, New York. 



Melocrinus parvus W. and Sp. 



Plate XXII. Fig. 8, 



1893. W. and Sp, ; Amer. Geologist (September number), Vol. X., p. 144. 



A small and very slender species of the type of Melocrinus Roemeri, hav- 

 ing like that species fiNQ uniserial radial appendages. Dorsal cup obpyr- 

 amidal, the interradial spaces deeply depressed, and the cross-section at the 

 top of the costals distinctly pentalobate. The plates a little convex and 

 covered with obscure ridges. 



Basal cup almost cylindrical, its upper end slightly the widest, the lower 

 face completely covered by the column ; the plates as high as the radials, 

 and the interbasal and basi-radial sutures distinctly grooved. Eadials a little 

 longer than wide. First costals of the same proportions as the radials. 

 Second costals smaller, proportionally shorter, and irregularly axillary ; one 

 of their upper faces short and giving off an arm, the other a row of distichals, 

 which are followed by higher orders of brachials, and arms given off at inter- 

 vals from opposite sides. Interbrachials three at the regular sides, and four 

 at the anal side, the latter having three plates in the second row against two 

 at the other sides. Ventral disk convex, the interambulacral spaces a little 

 depressed ; composed of moderately large, slightly convex plates. Arms 

 excentric. 



Horizon and Locality, — Niagara group ; St. Paul, Ind. 



Ty^e in the collection of Wachsmuth and Springer. 



i^emar^s. — This species differs from M. Roemeri in the narrower and 

 less spreading base, in the proportions of the radials and costals, and in the 

 convexity of the plates. 



