INDIANA PAL.CONTOLOGY. J48. 



The first radials are hexagonal; the second, quadrangular; the third, pen- 

 tagonal and axillary, supporting on each upper sloping edge a second axillary 

 plate. Each upper edge of this latter supports a series of three or four plates 

 to the arm bases. 



The first interradial is nine sided and the largest plate on the body. The 

 second interradial is quite large and apparently hexagonal. 



The plates of the ventral side are rather large and arranged as usual in the 

 species of this genus. 



This form may be compared with "Wachsmuth and Springer's species D. 

 tubui'culat If s yvhich was described from a fragmentary dorsal cup: and Miller 

 and Gurley's D. ccelatus, a much smaller species and with two less arms. 



The type specimen is from the Upper Devonian beds, near Charlestown, 

 Indiana, and belongs to the G. K. Greene collection. 



DOLATOCRINUS CORPOROSUS, Var. Concinnus, N. Var., 



(Rowley) 



Plate 44. Figs. 4, 5, 6. 



This crinoid differs in a few minor details from Miller and Gurley's species, 

 principally in the more elaborate sculpturing, the much less size of the basal 

 concavity, smaller basal canal and the ornamentation of the ventral surface. 

 Ill the latter respect, it agrees well with Wachsmuth and Springer's D. icosi- 

 dacfylus, a species with a much greater convexity of vault. 



Radial ridges pass up the middle of the radial series of plates from the 

 base to the arm openings but become almost obsolete between the first and second 

 radials, growing stronger as they approach the periphery. 



The central nodes of the plates are much smaller than on D. mult'niodosus 

 and those on the interradial plates are quite small. The first radial nodes con- 

 nect with the low basal rim by one or two sharp ridges each and the space be- 

 tween these nodes is filled by from four to seven transverse ridges, not connected 

 with the nodes, however. 



The central node of the very large first interradial is the center from which 

 radiate about thirty-six knotty ridges that pass to the nodes of the radial series 

 and that of the second interradial plate, four to each. Some of these ridges 

 coalesce with the interradial node and some do not. None of them, however, 

 are connected with the radial nodes or ridges. 



Small tuburcular nodes stand at the ends of some of the ridges, near the 

 central-radial and interradial nodes. 



