I 66 NEW YORK STATE MUSEUM 



similarity in ornament to the species M. tiff any i described by Wachs- 

 muth and Springer' from the Hamilton beds of New Buffalo, Iowa. That 

 species however is without the spinate nodes and an ornament of six ridges 

 radiating from the centers of the plates is not at all unknown in species of 

 earlier Devonic age e. g. M. p ach y d a c t y 1 u s (Conrad) Hall [Palae- 

 ontology of Xew York v. 3, pi. 3, fig. 2] of the Helderbergian. The 

 internal cast of this calyx exhibits in an interesting way the configuration 

 of the interior of the plates and exposes the filling of the vault which was 

 covered by the Orthonychia. The fragment of the column shows the 

 alternating size of the disks and the: scalloped edges of the major members. 



1 North American Crinoidea : Crinoidea Camerata. 1 S97. 1 : 299, pi. 22, fig. 7a. b. 



