316 SMITHSONIAN INSTITUTION 



species ; being very imperfect, with nothing above the first secundibrachs preserved, the 

 definition of the species is not so close as could be wished. The later discoveries have increased 

 the number of species to five, which may be characterized as follows : 



The Species of Etjryocrinus 



I. Surface smooth or finely granulose. 

 Calyx elongate, with straight sides. 

 Radial series with median elevation. 

 IBB large, but within column facet. 



BB visible as elongate triangles E. barrisi. 



Calyx broadly spreading. 



Radial series broadly convex. 

 Base rather small and narrow. 

 IBB very small or atrophied. 



BB extending little or not at all beyond column. 



iBr small and narrow, limited to I or 2 ranges E. concavus. 



iBr large E. tennesseensis. 



Base broad. 



iBr large, in several ranges of wide plates E. rofei. 



II. Surface tubercular. 

 Base large. 



BB extending well beyond column E. granulosus. 



Euryocrinus barrisi n. sp. 



Plate XL, figs. 1-3 



A large species, with elongate crown; broadly truncate and excavate at the 

 base ; height, 50 mm. ; width at IIIBr, 24 mm. ; base, 10 mm. Calyx with nearly 

 straight sides, spreading from outside of basal rim to top of I Ax, 1 to 1.5. Cross- 

 section at first bifurcation sharply pentagonal. Arms closely abutting to third 

 axillary, with a more or less angular median elevation, and raised winged but- 

 tresses at sides of brachials ; they are broad below, tapering rapidly with rather 

 short divisions to four bifurcations, beyond which they are more rounded and 

 divergent. Sutures arcuate. Base broadly and shallowly concave. iBr few, 

 spaces narrow with the rays meeting above them. Surface smooth, except for 

 the angularities and marginal elevation of the brachials. 



IBB rather large for this family, but entirely within BB, and not filling the 

 column facet. BB large, forming the greater part of the basal rim, and visible 

 in side view as good-sized elongate triangles ; post. B narrow and very elongate, 

 nearly as high as RR, followed by one anal plate with a few others succeeding 

 in one principal series and some smaller plates at the side. iBr 1, moderately 

 large, angular, with one or two smaller ones following in large specimens; 

 arched over by the wing-like projection of the axillaries; illBr sometimes pres- 

 ent. RR large, wider than succeeding IBr, their lower angles curving into the 

 basal cavity. IBr 3, short and wide, increasing in width to the axillaries. IIBr 

 3 ; IIIBr 4 or 5 inner, and 8 or 10 outer ; plates of these series as well as the upper 



