BATOCEINID^. 423 



In the form of the calyx, arrangement of the plates, number of arm 

 openings, and the ornamentation, ahnost identical with the preceding form ; 

 the specimens, however, are larger, the arms paired and somewliat more 

 slender. The two arms are given off from a diminutive axillary, which occu- 

 pies the same facet with tlie proximal arm plates. Occasionally one or more 

 of the arras are single, and in a very interesting specimen of D. orujinarius 

 (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 Boouville, Mo. 

 Ti/2}es in the collection of Wachsmuth and Springer. 



Remarks. — 1\\ the specimens which Miller described under Batocrinus 

 loonvillensis and B. 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). 

 PMe XXXIII. Figs. 8a, i. 



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. 

 Eadials comparatively small, once and a half as wide as long. First costals 

 a little narrower than the radials, twice as Avide 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 2 X 2 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 



