316 New Species of Crinoidea from the 



thors.* Both occur in the same association, and that has 

 also all the characteristics of Scaphiocrinus. 



Geological formation and locality. In rocks of the age 

 of the Keokuk limestone, Crawfordsville, Indiana. Collec- 

 tion of Wabash College. 



Scaphiocrinus cequalis (n. s.). Calyx small, rather broad- 

 ly expanding to the top of the first radial plates. Basal 

 plates minute, concealed by the column. Sub-radial 

 plates proportionally large, three hexagonal and two hep- 

 tagonal. First radials sub-pentangular, three times as 

 wide as high. Second radials as large as the first, quad- 

 rangular, broad, and short. Third radials pentangular or 

 sub-triangular, broader than high, strongly pointed above. 

 First anal plate less than half the size of the sub-radials 

 and resting between them, pentangular ; the succeeding 

 ones smaller, form and number not determined. 



Arms two from each ray, rising from the third radial 

 plate, bifurcating on the sixth, seventh, or ninth plate, 

 each division again dividing, but at a greater distance 

 from the last, rarely branching a third time, composed of 

 very short, wedge-form plates, the sides alternately short 

 and long, smooth in the lower part of the arm, but above 

 the last bifurcation becoming imbricated from the overlap- 

 ping of the upper margins ; branches strong below and 

 attenuate above. Tentacula long, strong, rising from the 

 longest side of the arm plates. 



This species may be distinguished from others, which 

 it resembles in general form, by the protuberant sub- 

 radial plates, the three radials in each series, the less 

 number of arm branches, and the number of arms in the 

 anterior ray being equal to that in the other rays. 



Geological forrnation and locality. In rocks of the age 



* ]n one specimen which I huve relerrod to, the (yntliocriniis clccadactijlus of 

 Lyon and Ciissedny, there ure four tinal phites visible, tlie lower or pentiingulnr cor- 

 responding with the same as described by these authors. 



