SS —— = p. 
BATOCRINID&. 493 
In the form of the calyx, arrangement of the plates, number of arm 
openings, and the ornamentation, almost identical with the preceding form ; 
the specimens, however, are larger, the arms paired and somewhat more 
slender. The two arms are given off from a diminutive axillary, which occu- 
pies the same facet with the proximal arm plates. Occasionally one or more 
of the arms are single, and in a very interesting specimen of D. originarius 
(typical form), which had evidently lost two of its single arms during life, 
these were replaced by two pairs, which are developed to only one half the 
length of the others. 
Horizon and Locality. — Upper part of Keokuk group at Bono, Lawrence 
Co., Ind., and in the lower part of the Warsaw limestone at Boonville, Mo. 
Types in the collection of Wachsmuth and Springer. 
Remarks.—In the specimens which Miller described under Batocrinus 
boonvillensis and LB. mediocris, the double arm structure is only partly 
developed; some of the arms being single, others paired. The modifications 
thereby produced in the arm formula probably led Miller to regard them as 
specifically distinct. 
Dizygocrinus cantonensis W. and Sp. (nov. spec.). 
Plate XX XIII. Figs. Sa, 0. 
Calyx depressed; the dorsal cup very short, rapidly and uniformly 
spreading to the bases of the free arms; its sides straight or slightly convex, 
the plates flat and apparently without ornamentation. 
Basals short and narrow, forming a circular ridge around the column, 
Radials comparatively small, once and a half as wide as long. First costals 
a little narrower than the radials, twice as wide as long, quadrangular, their 
lateral faces convex. Second costals pentangular, somewhat wider and 
longer than the first. That of the anterior ray supports two rows of two 
distichals, which are as large as the radials and support the arms. The 
costals of the four other rays have at one side an axillary distichal, followed 
by 2x2 palmars, at the other two large distichals, thus making the arm 
formula 3, 3, 2. The arm-bearing plates support at their upper facet a small 
trigonal axillary, and at each side of it an arm plate. Arms far apart, paired, 
rather long, incurving, rounded in the lower portions, but distinctly flattened 
and almost twice as wide in the upper. Pinnules rather stout and long. 
Interbrachials four to five, joining the interambulacral pieces; the anal 
a 
