424 THE CEINOIDEA CAMERATA OF NORTH AMERICA. 



interradins consists of 1, 3, 2, and 2 plates. The ventral disk is hidden by 

 the arms in all our sjDecimens. Anal tube composed of flat pieces; it is 

 rather stout and long, reaching. to nearly an inch beyond the tips of the 

 arms, and evidently was still longer. Column small, composed of thicker and 

 thinner joints with rounded edges. 



Horizon and Locality. — Keokuk groupj Canton and Edwardsville, Ind. 



Types in the collection of Wachsmuth and Springer. 



Remarks. — This species has its closest affinities with the preceding form, 

 but is readily distinguished by its larger size, the more abrupt spreading of 

 the dorsal cup, the greater length of the anal tube, its spatulate arms, and 

 by having fourteen pairs of arms instead of sixteen. 



Dizygocrinus unionensis (Woethen). 

 Plate XXXV. Figs. 16, 17, IS, 19, 20. 



1884. Batocnnm umotiensis — "Worthen ; Bull. II. of Illinois State Museum, p. 26. 



1890. Batocr'ums miionensis — Wohthen ; Geol. Rep. Illinois, Vol. VIII., p. 84, Plate 12, Figs. 5, 5ff, 

 and Plate 13, Pig. 3. 

 Syn. Bator.rinus jndcheUus — S. A. Miller ; 1891, Adv. Sheets 17tli Geol. Rep. Indiana, p. CS, Plate 



11, Figs. 13 aud 11. 

 Syn. Batoerinus Davki — Rottlet and Hake; 1891, Kansas City Scientist, p. 116, Plate 3, Fig. 9. 

 Syn. (?) Antinocrinus Caroli — Hall; 1860, Suppl. Geol. Rep. loiva, p. 54. 



Of moderate size. Calyx depressed ; the dorsal cup shorter than the 

 ventral disk, almost saucer-shaped ; the upper brachials placed nearly at 

 right angles to the axis of the calyx. Plates slightl}^ convex, covered with 

 obscure granules, the median portions of the radials and costals marked by 

 small transversely arranged nodes, which are confluent and form ridges. 

 Suture lines more or less grooved. 



Basals short, annular, slightly projecting beyond the column. Eadials 

 twice or three times as wide as long, their upper faces concave. Costals as 

 long as the radials but narrower ; the first quadrangular, the second pentan- 

 gular or heptangular. Distichals 2X2, followed by two rows of palmars, 

 except in the anterior ray which has three successive distichals. Pal- 

 mars and distichals of similar form, and as large as the costals. Arms 

 single, generally eighteen, arranged at equal distances around the calj'x ; 

 of moderate length, rounded on the back, and biserial from the second 

 free plate. The two proximal arm plates quadrangular, somewhat wedge- 

 shaped, and as large as the first palmars. Pinnules stout ; their joints 



