MESOZOIC RADIATA. 57 



have been a fault of tlic artist ; Forbes however has I presume 

 seen the species, as he describes it (Mem. Geol. Survey, vol. ii. 

 part 2. p. 477) in accordance with Charlesworth^s figure, also re- 

 ferring it to Goldfuss's species, but without referring to the 

 figure of that author, which is most accurate. 



Not uncommon in the calcareous grit of Filey Brig, Yorkshire 

 coast. 



{Col. University of Cambridge : three specimens.) 



[Echinida.) 

 Echinus petallatus (M^Coy). 



Sp. Char. Conoidal (diameter IJ inch, height 1 inch 2 lines), 

 base slightly contracted, obscurely ten-lobed ; ambulacra) area; 

 half the width of the interambulacral, three oblique pairs of 

 pores in each row ; the ambulacral and interambulacral spaces 

 have each an elliptical, petal-like, concave, smooth space ex- 

 tending from the vertex nearly to the base, each space being 

 one-third the width of its respective area ; the upper two-thirds 

 of the ambulacral arese have but one row of large tubercles on 

 each side, surrounded by a circle of very minute granules; 

 towards the base where the smooth central space stops there 

 are four rows of large tubercles ; the upper third of the inter- 

 ambulacral spaces has but two rows of large tubercles with 

 their circle of small granules, but they gradually increase to- 

 wards the base, and at the end of the smooth space there are 

 about eight rows. 



This is allied to the E. gijratus (Ag.), but is distinguished by 

 having the elliptical smooth spaces in both the interambulacral 

 and ambulacral areas ; the present is also a larger and more co- 

 nical species. 



Not very uncommon in the coralline oolite of Calne, Wiltshire. 



[Col. University of Cambridge.) 



Echinus diademata (M^Coy). 



Sp. Char, Conoidal (diameter of one specimen 10 lines, height 

 6 lines), base abruptly flattened, subpentagonal from the pro- 

 minence of the ambulacra, which are slightly convex and one- 

 half the width of the interambulacra ; interambulacra having 

 a concave, smooth, narrow space in the middle of their upper 

 portion, the middle of each half bears one row of about twelve 

 large primary tubercles, their wide smooth disc surrounded by 

 a circle of minute granules, numerous granules being scattered 

 in the intervening spaces; only two or three very small se- 

 condary tubercles on the outside of the base of the primary 

 rows ; ambulacra with two rows of large primary tubercles each. 



