BATOCEINID^. 451 



tlian ttose between the other rays, and much more depressed. Eespi- 

 ratory pores large, in five pairs, placed interradially. Arms long, the 

 tips infolding; composed of two series of moderately long pieces. Near 

 the upper end the arms, which below are rounded on the back, grow almost 

 flat, however, without increasing in width, and the surface of each plate in 

 well preserved specimens is covered with two small nodes which, formed into 

 longitudinal rows, give to the upper jjart of the arm a file-like appearance. 

 Pinnules long, composed of elongate joints, each one provided with a small 

 hook at the upper face. Regular interbrachials from one to three. Anal 

 plate higher than wide, followed by 3, 3, and 1 plate, the latter piece rest- 

 ing between the arm-bearing brachials. Plates of the ventral disk almost 

 flat, except the posterior oral, which is moderately convex and very large ; 

 it is erect, and forms at the anterior side the base of the anal tube. The 

 tube is almost central, very stout at the base, extremely long, attaining 

 sometimes twice the length of the arms, and it terminates in a very slen- 

 der point. The stem, which is known to a length of about 15 cm., retains 

 nearly the same width throughout. To the length of about 5 cm., smaller 

 joints alternate at intervals with larger ones, thence downward the plates 

 gradually become uniform. The larger or nodal joints throughout the stem 

 are about 1 mm. high by less than 2 mm. wide. Toward the lower end ap- 

 pear cirri, given oif irregularly, and only one from a plate. Axial canal 

 small, pentagonal. 



Horizon and Locality. — Upper Burlington limestone. It is found wher- 

 ever this bed is exposed throughout Iowa, Illinois, and Missouri, being one of 

 the two most common Crinoids of this horizon, and very characteristic of it. 



Macrocrinus jucundus (M. and G.). 

 Plate XXX. Figs. 13, IJf- 



1S90. Batocrims JKCitndus — 'i.lii.UKB. and Guklet ; Joum, Cincin. Soc. Nat. Hist., Vol. XIII., p. 20, 

 Plate 4, Figs. 5 and 6. 

 Syn. Batocrimis cignatus~%. A. MiLLEK; Adv. Sheets 17tli Hep. Geol. Suit. Indiana, 1891, p. 53, 

 Plate 8, Figs. 1 and 2. 



A small species, the calyx subovoid. Dorsal cup higher than the ventral 

 disk, truncated at the bottom ; the sides moderately convex ; the arm-bear- 

 ing plates projecting outward. The plates in most of the specimens are 

 almost flat ; in some, however, the middle part of the radials is formed into a 



