BATOCRINID 2. 451 
than those between the other rays, and much more depressed. Respi- 
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 part 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 off 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, 14. 
1890. Batocrinus jucundus—MituER and Guriny; Journ. Cincin. Soc. Nat. Hist., Vol. XIII., p. 20, 
Plate 4, Figs. 5 and 6. 
Syn. Batocrinus agnatus —8. A. Mittzr; Adv. Sheets 17th Rep. Geol. Surv. 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 
a a 
