CRINOIDEA OF THE WAVERLY GROUP. 165 



acter, with other differences of less importance, it seems proper to recog- 

 nize this form as a distinct species, under the name used to designate the 

 varietal form. 



Formation and locality: In shales of the Waverly sandstone group, at Richfield, 

 Summit county, Ohio. 



ACTINOCRINUS VIMINALIS. 



Plate 11, figs. 12-14. 



Aclinocrinus viminalis; 17th Rept. on the N. Y. State Cah. of Nat. Hist., p. 54. Extr. 

 published 1863. 



Body short and spreading, broadly cyathiform, and deeply lobed at the 

 rays. Basal plates very small ; first radial plates proportionally large ; 

 second radial plates broad, quadrangular; third radials very short and 

 broad, pentangular, supporting brachial plates on their upper sloping 

 sides. 



Arms two from each ray, simple at their origin, and composed of a 

 double series of plates beyond the third or fourth above the third radial. 

 The arms are usually almost regularly bifurcating near the base, and 

 unequally divided above. Ab^ve the first bifurcation, on6 of the divi- 

 sions often continues simple, while the other becomes subdivided, and 

 not unfrequently both are subdivided. In the anterior ray of one in- 

 dividual the arm is bifurcated at the regular distance below, one divi- 

 sion again subdividing into three and the other into five arms or 

 branches. The mode of bifurcating differs from the ordinary forms of 

 Actinocrinus, where the arm is composed of a double series of interlock- 

 ing plates ; the usual mode being, that the axial plate extends entirely 

 across the arm at the base of the division, while in this one the axial 

 plate is small and pentagonal, intercalated between those of the outer 

 ranges on each side, which are continued without interruption. 



The interradial areas consist of one small plate below with two elongate 

 plates above, which are situated between the bases of the arms. The 

 first anal plate is smaller than the first radial ; and above this they have 

 not been determined. 



Dome large, ventricose, somewhat lobed in the direction of the rays, 

 composed of numerous small, flat, polygonal plates. 



Plates of the body little convex, somewhat elevated along the middle 

 or approaching to sub-angular, with surface striato-granulose ; plates of 

 the arms nearly smooth, with a sub-angular elevation near the upper 

 margin. 



