422 THE CEIXOIDEA CAMERATA OF KOETH AilEEICA. 



grow more convex upward. Interbracbials two ; the first almost as large as 

 the radials ; the second much smaller and arched over by the two upper 

 brachials. Anal plate considerably longer than the radials ; followed by 3, 

 2, and 1 plate ; the latter generally in contact with the interambulacral 

 pieces. Ventral disk a little shorter than the dorsal cup, hemispherical, 

 surmounted by a short slender anal tube; the plates convex. Column stout, 

 the older joints rounded at their edges and projecting. 



Horizon and Locality. — Upper j)art of the Keokuk group at Bono and 

 Canton, Ind. ; also in the Lower part of the Warsaw limestone at Boon- 

 ville, Mo. 



Types in the collection of Wachsmuth and Springer. 



Dizygocrinus Gurleyl (S. A. Millee). 

 Plate XXXIV. Fig. 19. 



1891. Batocrimis (?Krfe^i — MiLLEE ; Adv. Sheets Geol. Suit. Ind, (17tli Ecp.), p. 66, Plate 11, Figs. 

 9 and 10. 

 (Not Batocrinus Gurleyi Rotvley and Haee, Aug. 1S91). 



Of the type of Dizygocrinus originarius W. and Sp., and so closely resem- 

 bling it that there is much doubt if it is a good species. The specimens from 

 Bono, described by us as " Eretmocrinus " originarius, only differ from the 

 Boonville ones, which Miller has referred to Batocrimis Gurleyi, in having at 

 the regular sides three interbracbials in place of two, and sis pieces in place 

 of five above the anal plate. The arms are a little longer and more slender 

 at their tips, the angular ridges along the rays somewhat higher, and the 

 surface markings upon the plates a little more distinct. The sides of the 

 dorsal cup in one of Miller's types are concave, in the other convex; while 

 they are nearly straight in the Bono specimens. We give a figure of one of 

 Miller's types for comparison. 



Horizon and locality. — Lower part of Warsaw limestone, Boonville, Mo. 



I'ype in the collection of F. A. Sampson, Esq. 



Dizygocrinus originarius, var. adultus (W. and Sp.). 

 Plate XXXV. Figs. 14 and 15. 



1881. Eretmocrinus adultus — W. and Sp. ; Ee-rision Pateocr., Part 11., p. 175. 



SjTi. Batocritms mediocris — S. A. Miller; Adv. Sheets 17tli Eep. Geol. Surv. Ind., p. 62, Plate 



10, Tig. 9. 

 Syn. Batocrinus boonvillensis S. A. Millee; ibid., p. 65, Plate 10, Pig. 13. 



