BATOCEINID^. 41 7 



Dizygocrinus crawfordsvillensis s. A. Millek.* 



1S91. Batocriiius crawfordsvillensis, S. A. Milleb, ; Ady. Slieets 17tli Rep. Geol. Surv. ludiaua, p 64, 



Plate 10, Eg. 11. 



A rather small species. Dorsal cup obconical, truncated at the base, 

 nearly one half wider than high, the sides almost straight ; the radials and 

 brachials marked by well defined angular ridges, following the median line 

 of the plates and proceeding to the arm bases; the interbrachials convex, 

 covered with obscure radiating ridges. 



Basals .short, extended outward and forming a small rim ; columnar con- 

 cavity deep, occupying one half the diameter of the lower face. Eadials 

 considerably wider than long. First costals quadrangular, the length equal 

 to one half their width ; the second pentangular, of nearly the same propor- 

 tions as the first. Distichals two in the antero-lateral rays, followed by five 

 palmars, which support the arms. The anterior ray has five distichals and 

 no palmars ; while in the posterior rays the division adjoining the anal side 

 has two distichals and five palmars, and the opposite division five distichals, 

 making sixteen arm openings wit];i two arms from each opening, or thirty-two 

 to the species (not twenty-four, as stated by Miller). The arms are incurv- 

 ing, very delicate, and so short that when recurved they reach but little 

 above the summit of the disk. Regular interbrachials three, the first large, 

 the others quite small. The anal interradius consists of six plates including 

 the anal ; three in the first row, and two in the second. Ventral disk con- 

 vex, as high as the dorsal cup, the plates large and tumid. Anal tube nearly 

 central. 



Horizon and Locality. — Keokuk limestone ; near Crawfordsville, Mont- 

 gomery Co., Ind. 



Type in the collection of Professor Gorby. 



EernarJcs. — This species resembles Dizygocrinus indianensis, from which it 

 differs in the number of brachials, and in the more delicate and much 

 shorter arms. 



* We give no figure of tils species, as we were unable to obtain the type, and our description is made 

 after MiUer's. 



