428 THE CBINOIDEA CAMEEATA OE NORTH AMERICA. 



Remarks. — Professor Hall described this species as having but two plates 

 above the anal piece, which is certainly abnormal, as our specimens clearly 

 show the presence of three plates. 



Dizygocrinus montgomeryensis Woethen. 

 Plate XXXIII. Figs. 3, and 4, and Plate XLVI. Fig. 10. 



1S84. Batocrhms montgomeryensis — Worthen ; Bull. 2, Illinois State Mus. Nat. Hist., p. 25, and Geol. 

 Kep. Illinois, Vol. VIII., p. 83, Plate 12, Figs. 2, 2«. 

 Sjn. Batoorinus G-urlei/i — RowLET and Hake (not S. A. Miller), 1891, Kansas Citj Sclent., Vol. 



v., p. 115, Plate 3, Fig. 7- 

 Syn. Batoerimis Sweeti — Rowley and Hake, 1891, ibid., p. 116, Plate 3, Fig. 8. 



Calyx of medium size. Dorsal cup saucer-shaped, lower than the ven- 

 tral disk, rounded at the sides; the arm-bearing plates produced outwai-d in 

 form of tooth-like projections aroimd the calyx. Plates from perfectly flat to 

 slightly elevated, and without ornamentation. 



Basals small and short, forming a basin-shaped depression, which is com- 

 pletely filled by the upper stem joint. Radials twice as wide as long, the 

 upper face concave. First costals a little shorter and considerably narrower 

 than the radials ; the second slightly longer and somewhat wider. Distichals, 

 as a rule, longer than the costals. They consist in the anterior ray of two 

 series of four plates, which support the arms, the antero-lateral raj's have 

 2x2 distichals followed by three successive palmars in the calyx ; while the 

 two posterior rays in one division have four distichals and no palmars, in tlie 

 other — that adjoining the anal interradius — two distichals and three pal- 

 mars. The brachials of the two upper rows project outward, and are 

 rounded and grooved laterally at the suture lines. Arm openings sixteen, 

 the interspaces between the raj^s slightly widest ; the arm facet semi-circular, 

 and directed obliquely upward. Arms in pairs, given off in the usual way ; 

 they are long, very slender, tapering, and somewhat angular on the back ; 

 the joints of medium height, and their upper margins projecting over the 

 lower ones of succeeding pieces. Pinnules long. Anal plate not quite as 

 wide as the radials but higher, and followed by eight to nine interbrachials, 

 against three or four at the other sides, those of the anal side being always, 

 and those of the regular sides sometimes, connected with the plates of the 

 disk. Ventral disk tumid, the centre of the plates covered with a very small 

 tubercle. Anal tube slender, the plates smooth or slightly convex. Column 



