ECHINODERMA TA—CRINOIDEA . 557 



each interradial area. Tegmen comparatively flat, surmounted by 

 a large and almost central tube and with the interambulacral spaces 

 depressed. Arms biserial, generally bifurcating. Devonic. 



176. D. excavatus Wachsmuth and Springer. Devonic. 

 Very large, with width of dorsal cup three times the height, the 



R formed into a deep, sharply pentangular, funnel-shaped pit which 

 penetrates the calyx nearly to the arm regions. Surface of all 

 external plates covered with parallel ridges and keel-like projections. 

 Onondaga of Indiana. 



177. D. triadactylus Barris. Devonic. 

 Distinguished by the ornamentation, the ridges connecting the 



R being arranged in a pentagon which surrounds the basal pit and 



Fig. 1890. Dolatocrinus glyptus {D. ornatus Meek), basal and summit views. 

 (After Miller and Gurley. ) 



whose sides support five triangles, forming thus a 5-rayed star 

 in basal view. 



Hamilton of Michigan. 



178. D. glyptus (Hall). (Z). orwafw.y Meek.) (Fig. 1890.) Devonic. 

 Calyx depressed-globose, flattened to near the top of the R. 

 Hamilton of New York and Ohio. 



179. D. liratus (Hall). Devonic. 

 Differs from D. glyptus only in ornamentation ; the ridges which 



in D. glyptus are interrupted are continuous in D, liratus and all 

 the plates bear more ridges and prominences. 

 Hamilton of New York and Ohio. 



LXVH. EucALYPTOCRiNUS Goldfuss. 

 Calyx with a deep concavity at the lower end, the 4 B forming 

 the bottom and the R the sides of this inverted cup. Interbra- 

 chials 3, the first very large, followed by two narrower ones joined 



