374 THE CRINOIDEA CAMEEATA OF NORTH AMERICA. 



which are much wider than the first, supporting 2x2 palmars. The pos- 

 terior ray lias three distichals and no palmars. Arm facets slightly concave, 

 directed obliquely upward ; the ambulacral openings small and equidistant, 

 except the one between the posterior rays, which is not only wider but 

 a little indented. Structure of arms unknown. Regular interbrachials one 

 or two, the first large, the second, if present, quite small; roofed by the 

 palmars, except at the anterior side by the upper distichals. The anal plate 

 supports two rows of three plates, of which the middle ones are larger than 

 those at the sides ; the upper one rising to the height of the first palmars, 

 and arched over only by the arm bearing plates. Disk rising but little 

 above the upper margin of the cup; composed of highly convex, somewhat 

 tumid plates. The orals and radial dome plates — the latter of a first, 

 second, and third order — larger than the interambulacral plates. Anal 

 tube almost central, rather large at the base. 



Horizon and Locality. — Lower part of the Lower Burlington limestone ; 

 Louisiana, Mo. 



Tij2ye in the collection of Prof. Rowley, at Fort Smith, Ark. 



Eemarks. — This species departs from the typical Batocrinus in having 

 but eighteen arms, and in the position of the respiratory pores, which are 

 placed so closely to the ambulacral openings as to appear always confluent 

 with them in the specimens. It approaches Dizygocrinus in its general form 

 and the small size of the base. 



Batocrinus rotadentatus Eowlet and Hake. 

 Plate XLVI. Fig. 7. 



1891. Rowley aud Hare; Kansas City Scient., p. 102, Plate 2, Tigs. 17 and 18. 



Calyx wider than high, wheel-shaped, the base surrounded by a small rim. 

 Dorsal cup a little constricted above the basals, then curving rapidly outward 

 to the arm bases. Surface of plates smooth, slightly convex. 



Basals large, erect, rounded at the lower end, and forming a profound 

 concavity, which is completely filled by the upper stem joints ; the suture 

 lines deeply grooved. Radials nearly twice as wide as long, about half the 

 size of the basals, but as large as both costals together ; the latter quad- 

 rangular and pentangular, respectively. Distichals two, short, the second 

 larger than the first and axillary, except in the anterior ray, which has three 

 distichals and no palmars. The other rays have four arms each, and the axil- 



