I4J. CONTRIBUTION TO 



MEGISTOCRINUS EXPANSUS, Var. Magniventrus ? Rowley. 



Plate 41. Figs. 4, 5, 6. 



This fine specimen is referred doubtfully to variety magniventrus, differing 

 from that form in the slender elongated spines of the ventral disk and fifteen 

 arm bases instead of sixteen. 



The ventral tube is at the highest part of the dome, but located latterally. 



The basal and first radial plates form a shallow concavity. The arm bases 

 form strong lobes. 



The ambulacral fold or ridge to the left of the anal tube is without a spine, 

 all of the other folds possessing one each and with one at the center of the 

 vault. 



This specimen is figured mainly to show its spinose character and the ten- 

 dency toward ventral spines in these smooth forms. 



It comes from the same horizon, locality and collection as the last specimen. 



DOLATOCRINUS M ULTI B R A C H I AT U S , N. Sp., (Rowley) 



Plate 41. Fig. 7. 



This fine specimen preserves only the dorsal cup and that even is incomplete 

 on one side. 



The calyx is greatly depressed, the concave basal area extending beyond 

 the third primary radial. 



The radial ridges are greatly elevated or keeled on the first radials and 

 angular. 



The first, second and third radials are much wider than long. Each plate 

 of the second radial series is an axillary plate, so is each of the third and in one 

 of the rays or divisions even a fourth series plate is axillary. The whole giv- 

 ing rise to eight arm bases to the ray (one has nine), making forty-one arms in- 

 all, if the missing part of the dorsal cup was normal. The ventral disk is un- 

 known. 



The first interradial plate is large and above it is a second interradial. 



From a hardly noticeable central node on each interradial plate, numerous 

 fine raised lines radiate outward to the centers of adjoining plates. 



Similar raised lines radiate outward from the radial plates. 



This species seems to belong to the Excavatus section of Dolatoerinue but 

 may be readily identified by its great number of arm bases. 



The ornamentation of this species is most beautiful. 



Middle Devonian, Falls of the Ohio. 



Collection of Mr. G. K. Greene. 



