124 FIFTEENTH REPORT ON THE CABINET OF NAT. HISTORY. 



GENUS rORBESIOCRINUS (DeKoninck). 



FORBESIOCRINUS LOBATUS ( n. s.). 



Body less than the medium size of the genus, spreading somewhat 

 abruptly from the base to the third radial plates, from which the 

 arms rise almost vertically. Basal plates small and short, forming 

 a narrow ring around the base : subradial plates short, pointed 

 above ; rays prominent : radial plates abruptly bent inward at 

 the sides, the upper margins deeply sinuate for the reception of 

 the patelliform plate of the next superior joint; the third radial 

 marked by a prominent central node near its upper margin. 

 Interradial spaces deeply depressed, with numerous interradial 

 plates. Arms bifurcating on the third radial plate, and again two 

 or three times above this. Surface finely granulose. 

 The length of the bod}' and arms (which are incurved at the 



summit) is a little more than one inch. 



This species bears considerable resemblance, in general form and 

 proportions, to the F. giddingi of the Carboniferous limestone. 



Geological formation and locality. In the shales of the Hamilton group, 

 Ontario county, N.Y. C. A. White, collector. 



FORBESIOCRINUS NUNTTUS (n.s,). 



Body pentalobate below, subturbinate, regularly spreading from the 

 base to the free arms. Basal and subradial plates rudimentary, 

 the latter barely visible beyond the column-facet. The primary 

 radial series consists of three plates, which increase rapidly in 

 width from the lower one : interradial and anal plates apparently 

 none. Secondary radial series three, decreasing in width from 

 below upwards; the last one a bifurcating plate. On one ray the 

 arm bifurcates on the fourth plate, while the other division is 

 simple to the sixth plate, the seventh being apparently a bifurca- 

 ting plate. 



Surface strongly granulose or papillose, with a median ridge on the 

 centre of the plates, and a strong, short, obtuse, ascending spine 

 at the centre of the bifurcating plate. 

 The upper part of the column is round, enlarging upwards, and 



composed of thin joints so characteristic of the genus. The marks 



of the overlapping patelliform plates are well preserved in the rays. 



The close resemblance between this species and the 0. thiemei of the 

 Burlington limestone is very remarkable. It differs in the character of 

 surface and in the divisions of the ray, which are regularly bifurcated 



