INDIANA PALEONTOLOGY. iM. 



base. An almost circular rim surrounds the stem cicatrice. The columnar 

 canal is pentalobate. The radials and costals have each a strong central tuber- 

 cle, connected in the same ray by a more or less indistinct thread-like ridge. 



The centers of the interradials are occupied by a strong node from which 

 radiate sharp, more or less toothed ridges, passing to adjacent radial and inter- 

 radial centers. The ridges are interrupted at the sutures. The ornamentation 

 of the higher radials or distichals is a stellate arrangement of elongate nodes. 



The distichals of the one-costalled ray are bifurcating plates, supporting 

 palmars above as in other rays. 



The interbrachials of four inlerradial rays are three in number while the 

 anal interradius has but two. 



In the ventral disk the lower interradial (inter-ambulacral) plates are two 

 elongate pieces to each of the four areas, supporting above one or two plates. 

 In the anal area there are two short plates below, supporting three plates above. 

 The anal tube is sub-central and small. The ventral plates are ornamented by 

 small spine-like nodes except near the proboscis where the number is fewer and 

 the size larger. 



There are two respiratory pores to each arm base. 



This beautiful specimen is from the Upper Devonian, near Charlestown, Ind. 



DOLATOCRINUS SPINOUS US, M. <Sr G., Rowley. 



Plate 48. Fig. 4. 



Our drawing is of a symmetrical four-rayed dorsal cup. The basal concav- 

 ity is round and quite deep as in the Marshi group. 



The radials to the middle of the second costal are traversed by an extrava- 

 gantly strong keel. The plates are without central nodes. The ornamentation 

 is fine radiating lines. 



The specimen furnishes strong evidence against the erection of species upon 

 the number of arms alone. 



It probably had sixteen arms. 



Miller <k (iurley's figure is without ornamentation but they do not state that 

 fact in the description. As our specimen does not preserve the vault, there is 

 some doubt of the correctness of the reference. It might be placed with Wachs- 

 muth <k Springer's D. excavatus, but that species is probably a synonym of D. 

 spinosus, M. & G. 



The specimen is from the Falls of the Ohio and the Middle Devonian beds. 



