118 WELLE R. 



Melocrinus nodosus Hall. 



(PL XIV. Fig. 6.) 



1 86 1. Mclocrinites nodosus Hall, Rep. Prog. Geol. Surv. Wis., 



p. 19. 

 1895. Melocrinus nodosus Whitfield, Mem. Am. Mus. Nat. 



Hist, vol. I, p. 48, PI. V, fig. 14. 



Calyx pyriform, truncate at the base, sides straight or slightly 

 convex from the tops of the basals to the arm openings ; cross - 

 section, as seen from abov^e, exclusive of the nodes, obscurely 

 subpentagonal, greatest diameter at the arm bases. The plates 

 of the dorsal cup ornamented with conspicuous nodes. 



Basals four, projecting laterally into more or less prominent 

 nodes, columnar facet large, often somewhat depressed between 

 the nodes of the plates. Radials large, heptagonal and hex- 

 agonal, strongly nodose. First costals hexagonal, smaller 

 than the radials, strongly nodose ; second costals pentagonal 

 or heptagonal, smaller than the first and less strongly nodose. 

 Distichals smaller than the last costals, higher than wide, free 

 beyond the first pair. First interdistichals hexagonal, as large 

 as the first costals and bearing similar nodes, followed by two 

 smaller nodose plates in the second row, one of which often 

 bears a larger node than the other ; in the third row there are 

 two or three smaller plates and above these numerous small 

 plates which lead up to those of the vault. The posterior inter- 

 radius is not differentiated from the other four. 



Ventral disk depressed convex or nearly flat, composed of 

 small polygonal nodose plates of nearly equal size ; marked by 

 more or less prominent rounded ambulacral ridges which ex- 

 tend from the arm bases towards the center ; and surmounted 

 hy the base of a subcentral proboscis whose height cannot be 

 determined. 



Remarks. This species, although described, but not illus- 

 trated, by Hall in 1861, is not recognized by Wachsmuth and 

 Springer in their recent monograph, it being passed over with 

 the remark that it was described from imperfect casts. ^ The 



1 The North American Crinoidea Camerata. By Chas. Wachsmuth and Frank 

 Springer. Vol. I, p. 294. 



