540 



NORTH AMERICAN INDEX FOSSILS. 



130. G.kentuckiensis (Shumard). (CnyssaUsLll) (Fig. 1869.) 



Devonic. 



Differs from G. carinatus in the greater number of distichals, 

 two to each of the ten costals instead of one to each ; differs also 

 in the unequal size of the R and second costals, the latter being half 

 the size of the former. 



Hamilton of Kentucky. 



131. G. eucharis (Hall). Devonic. 

 Differs from G. carinatus in the relative size of R and second 



costals, the latter less than half the size of the former. 

 Hamilton of New^ York. 



132. G. carinatus E. Wood. (Fig. 1870.) Devonic. 

 Distinguished by its delicate ornamentation of thin carinse. R 



and first and second costals of about equal size. 

 Hamilton of Indiana. 



Fig. 1870. GenncBocrinus carinatus^ three views of the type, X K- 

 (After E. Wood. ) 



XLVI. Batocrinus Casseday. 



Similar in form to Aciinocrinus, but rays not lobed and calyx 

 plates without sculpturing. R very large, six- or seven-sided. 

 First costals quadrangular, always shorter than the R and trans- 

 versely arranged. Arm openings equidistant and directed hori- 

 zontally. Tegmen elevated, its plates heavy, more or less swollen 

 and of nearly equal size except the posterior oral which is larger 

 and from which rises the anal tube. Anal tube nearly central, very 

 long and gradually tapering. Arms 20-26, simple, biserial and 

 very short. Respiratory pores 20. Column stout, round. 



Differs from Eretmocrinus in having stout and cylindrical arms 

 instead of paddle-shaped ones and in the greater length of the 

 anal tube; from Eutrochocrinus and Dizygocrinus in the simple 

 arms. Mississippic. 



