BATOCRINID.2. 5397 
to the foot of the palmars; the latter slightly projecting outward. Surface 
of plates elevated ; the radials raised into conspicuous transverse nodes; the 
brachials keel-shaped, forming angular ridges, which branch to the bases of 
the arms ; the first interbrachials tumid, the succeeding ones almost flat. 
Base moderately high, notched at the sutures; the lower edges project- 
ing laterally, and forming a well defined rim; the bottom rather deeply 
excavated for the reception of the column. Radials very large, three times 
as wide as the first costals; the latter unusually small and quadrangular ; 
the second costals somewhat larger and pentangular. Distichals 2 x 2, of 
the size of the costals. Palmars 2 X 4, in contact laterally, except at the 
posterior side where they are generally separated by a small interbrachial 
piece. Arm openings nearly equidistant, only the space between the two 
posterior rays being a little the widest and slightly depressed. Arms long, 
slender, incurving, subcylindrical to one third their length, then gradually 
flattening and expanding to once and a half their lower width; their sides 
knife-like and serrated along the edges. Interradial spaces somewhat 
depressed; the first interbrachial very large, supporting two small plates 
in the second row. Anal plate a little higher than the radials, and formed 
into a circular node instead of a transverse one; followed by three, two, and 
one plate. Ventral disk hemispherical, somewhat bulging toward the sides. 
Plates large and slightly convex. Between the plates at the periphery there 
are upon the surface narrow but deep vertical grooves, which lead to the 
respiratory pores. ‘The pores are large and arranged in the usual manner. 
Anal tube excentric, very long, stout, retaining the same width to near its 
upper end, where it tapers rapidly and is pierced by a minute opening. At 
about half its length, it curves abruptly at right angles, and passes out 
laterally between the sides of the arms. Column moderately large, com- 
posed near the calyx alternately of thicker and thinner joints. 
Horizon and Locahty.— Lower part of the Upper Burlington limestone, 
Burlington, Iowa. 
Types in the University Museum at Ann Arbor, and in the Museum of 
Comparative Zodlogy. 
Remarks. —The peculiar structure of the anal tube, to which we allude 
in the description, occurs in all our specimens, and has been observed also in 
a/fine specimen in the Museum at Cambridge. 
Hall, in his Preliminary Descriptions of New Crinoids, p. 14, mentions 
a form to which he applied the name Actinocrinus matuta, var. attenuata ; but 
