PALSE')NT0L9&IJAL REPORT OF GEOLOGICAL SURVEY. 473 



quite thick pieces, those adjoining the thick pieces are quite thin, with 

 one much thicker between ; nearer the body the pieces are alternately 

 larger and smaller; their edges are slightly rounded. 



Basal pieces, two of equal size, nearly alike ; united they form a 

 shallow elliptical cup, the upper margin being indented by four concave 

 and two angular notches, swelling below the margin of the cup. The 

 inferior surface presents an imperfect elliptical depression, in'the centre 

 of which lies a deep circular pit, concave at the bottom ; the outer mar- 

 gin of which is marked around its circumference by grooves and ridges, 

 by which it is joined to the column. 



Primary radials five, differing in form ; the piece opposite the anal 

 side is slightly concave on the upper margin ; the ends are nearly par- 

 allel to each other ; twice as broad as high ; the inferior margin is an- 

 gularly pointed — the point being about the centre of the width of the 

 piece, at which point it is twiee as high as at the ends. The four other 

 primary radials are convex below, and fit into the concave indentations 

 of the basal pieces ; they are low and broad ; not quite as high as the 

 first pieces ; two are concave above, the lower and upper margins being 

 nearly parallel ; the other two have two concave depressions above, of 

 unequal size ; the ends of the four pieces are obliquely diverging from 

 below upwards — the ends joining the anal piece having the greatest 

 divergency. 



Secondary radials. These are in two series, the first consisting of 

 ten pieces, no two of which are alike ; those resting on the first radial 

 opposite the anal side are convex below ; as broad as high, the upper 

 margin of each having two concave indentations ; the junction of these 

 pieces with each other is square, the opposite ends terminating in an 

 angular point. The secondary radial pieces resting upon the first 

 radial piece, to the right of the anal piece, are terminated at both ends 

 by angular points ; from one of these rise three secondary radials of 

 the second series ; from the other, only one. 



The next secondary radials to the right are, probably, broken, and in 

 our specimen are represented by four quadrangular pieces of unequal 

 size. The other four pieces are nearly of equal size, sub-quadrangular ; 

 twice as broad as high, having two concave notches in the upper mar- 

 gin of each. 



Secondary radials. The secondary radials are twenty in number ; 

 60 



