326 New Species of Crinoidea from the 



radials hexagonal, less than half the size of the first; 

 third radials heptagonal, larger than the second, supporting 

 on their upper sloping sides the supra-radials, two of which 

 are hexagonal, and equal in size to the second radials ; the 

 upper one of these is the foraminiferous plate, and above 

 this arc two others, the upper one of which supports the 

 arm-like processes of the summit. 



The interradials consist of six ranges of plates : the first 

 a single pentagonal or hexagonal plate, larger than the 

 succeeding, but smaller than the first radials ; two or three 

 in the second range ; three in the third and fourth ; two in 

 the fifth ; and two in the sixth ; these plates are generally 

 hexagonal, some pentagonal, and others heptagonal. The 

 anal area differs from the interradial only in having a 

 greater number of plates. 



The summit arms are composed of a double range of 

 semi-elliptical plates, each of them perforated by a small 

 circular foramen. The foraminiferous areas are very 

 small, the first plate is minute, hexagonal, succeeded by 

 two still smaller plates, which margin the foramen. Upon 

 the inner oblique side of the second supra-radial plate 

 rests a sub-circular plate, with a deeply notched upper 

 margin, which forms the base of the arms of the forami- 

 niferous areas. 



Surface marked by a series of ridges which commence 

 on the sub-radial plates, and radiate from the centre to 

 the sides, except on the sides adjoining the basal plates ; 

 the ridges on the radial series are much stronger and more 

 highly elevated ; they give the surface a reticulate appear- 

 ance, and the minute surface markings are finely gran- 

 ulose. 



This species is distinguished by the strong radial ridges, 

 and the reticulate surface produced by the ridges of the 

 intermediate plates joining with those of the ray. 



Geological formation and locality. Burlington lime- 



