484 



NORTH AMERICAN INDEX FOSSILS. 



Fig. 1796. ElcBacri- 

 n us verneuili vAx.pomum . 

 (After Eth. and Carp.) 



18. E. verneuili (Troost). (Figs. 1786, 1795.) Devonic. 



Radial plates very short, with scarcely any subdivision into 

 bodies and limbs. Ambulacra very short and 

 narrow. (Type of genus.) 



Onondaga of Kentucky, Indiana and Ohio. 



1 8a. E. verneuili var. pomum Etheridge and 



Carpenter. (Fig. 1796.) Devonic. 



Distinguished by its almost globular calyx. 



Onondaga of Ohio and Indiana. 



19. E. elegans (Conrad). (Fig. 1797.) 



Devonic. 

 Pentalobate ; summit plates five instead of 

 seven or more as in E. verneuili. 

 Hamilton of New York. 



20. E. obovatus Barris. Devonic. 



Calyx more elongated than in other species of the genus. 

 Hamilton of New York, Michigan and Iowa. 



VIII. ScHizoBLASTUS Etheridge and 

 Carpenter. 



Calyx globose, pentagonal-globose, or melon- 

 shaped. Section 5- or lo-sided. Basal plates 

 sometimes very slightly visible in side view. 

 Radials either long or short. Deltoids of 

 variable size but always visible in side view. 

 Ambulacra very narrow, extending the whole 

 height of the calyx. Lancet plates sometimes 

 largely concealed by the side plates. Hydro- 

 spire folds one to four on each side of an am- 

 bulacrum. Spiracles small, appearing as Hnear 

 slits between the lancet plate and the deltoid 

 ridges ; posterior pair either confluent with the anus or opening 

 separately on each side of it under a '' hood." Surface usually 

 ornamented with granular striae. ^ 



Differs from Granatocrinus in the position of the spiracles. 

 Mississippic. 



Fig. 1797. Elceacri- 

 mis elegans, natural size 

 and enlargement of one 

 inter-ambulacral space. 

 (After Hall.) 



