batocei:nid^. 421 



subcirciilar with a small notch at the upper end, and provided with a trans- 

 verse, imperforate ridge. Arms single, so far as can be ascertained from the 

 facets ; their strncture not known. Regular interbrachials : 1, 2, 2 ; the first 

 large and considerably wider than high; the upper range, which sometimes 

 consists of but one plate, arched by the palmars. Anal plate short, followed 

 by seven or eight plates. Ventral disk conical, surmounted by a large, 

 nearly central anal tube. Plates of the disk comparatively large and tumid \ 

 the orals somewhat larger and in contact ; the posterior one erect, and 

 forming a part of the tube. Ambulacral plates represented by three sharjDly 

 nodose plates of a first and second order. 



Horison and Locality. — Warsaw limestone ; Spergen Hill, Ind., and 

 Barren Co., Ky. 



Remarks. — This species has its closest affinities with D. TFJutci W. and 

 Sp., but the cup is less deep, and the tegmen in proportion much higher. 



Dizygocrinus originarius W. and Sp. 

 Flafe XXXIII. Figs, la, b. 



IS8I. Eretmorriims origimruis — W. and Sp. ; Revision Pateocr., Part II., p. 174. 



Sjn. EretmoQnnusmi-sooieims — ^CB.-rsi:s.^; 1S82, Geol. Kep. Ulinois, Vol VII p 306 P]-ite'>8 

 Fig. 14. . r- . ' - , 



A small species of the type of Bizygocrinus Wliitei. Calyx biturbinate, as 

 high as wide ; the dorsal cup a little higher than the ventral disk, with almost 

 straight sides and broadly truncated base; arm regions projecting, and some- 

 what indented at the interradial spaces. Plates slightly convex, covered 

 with obscure grannies, and the radials and brachials marked by a faint longi- 

 tudinal ridge, which bifurcates and sends branches to the arms. 



Basals a little larger than in any of the preceding species; forming 

 a short, broadly truncated cup, with a shallow columnar depression, the 

 sides somewhat projecting and slightly grooved at the sutures. Eadials as 

 large as both costals together, wider than long. First costals quadrangular, 

 twice as wide as long; the second a little wider and pentangular. Distichals 

 two or three; the anterior ray has three, followed by arm plates; the antero- 

 lateral rays two, followed by two rows of small palmars ; the posterior rays 

 have two at one side, followed by 2 X 2 palmars, and at the opposite one 

 three successive distichals. Arms sixteen, simple, stout in proportion to the 

 small size of the species, rather short, and somewhat flattened at the tips ; 

 they are composed from the second plate up of two series of pieces, which 



