320 THE FOSSIL ECHINOIDEA 



is greater than the anterior, whilst the slope of the test from the dome to the margin 

 is rather more rapid anteriorly than posteriorly. 



The apical disk is subcentral, or very slightly excentric in front. The ambulacral 

 petals are short, wide, petaloid, very full and widely rounded, almost closed at the 

 outer extremity, and prominently tumid. The odd anterior ambulacrum is slightly the 

 longest : and the antero-lateral pair are subequal to, or very slightly shorter than, the 

 posterior pair. The greatest width of the paired petals is opposite to, or even a little 

 beyond, the commencement of the outer third, and is proportional to the length as 5 : 8, 

 the actual dimensions of the postero-lateral petal in the example under description 

 being 24 millim. long, and its greatest breadth 15 millim. The poriferous zones are 

 very wide on the outer part of the petal, their breadth increasing gradually from the 

 apical extremity until within a few pairs of pores of the outer extremity, the latter 

 diminishing rapidly. The conjugating furrow which unites the pores of a pair is faint 

 and indistinct, and its position is very oblique in relation to the zone, the degree of 

 obliquity increasing as the outer extremity is approached, until the outermost pairs of 

 pores are nearly parallel with the median axis of the ambulacral area. The intervening 

 costse are low and rather narrow, and are ornamented with a row of 5 or 6 small primary 

 tubercles widely and equidistantly spaced amongst the close granulation. The broadest 

 part of the poriferous zone is 4 millim. and is wider than half the interporiferous 

 area at that place. The widest part of the interporiferous area is nearer midway 

 between the extremities and measures 7 '5-8 millim. in the antero-lateral petals, and is 

 a trifle broader in the posterior pair. The odd anterior petal is generally similar in 

 detail to the paired petals just described, excepting that it is not so full, or rounded so 

 abruptly, at the outer extremity. The distance of the paired petals from the margin is 

 about equal to their own length. 



The interradial areas are extremely narrow and band-like near the apex, on 

 account of the expansion of the petals. The ornamentation of the interradia and inter- 

 poriferous areas consists of very small primary scrobiculated tubercles, with the inter- 

 spaces about equal to, or occasionally very slightly greater than, the diameter of the 

 scrobicules, the interspaces being filled with small, but distinctly spaced and definitely 

 semiglobular, uniform, miliary granules. 



The actinal surface is concave, with the peristome deeply impressed ; the concavity 

 commencing very near to the margin and increasing gradually inwards, the surface 

 lying between the peristome and the margin being individually gently convex. The 

 ambulacra are in shallow widely-expanding grooves. 



The periproct is small and perfectly circular, situated rather more than its own 

 diameter away from the margin. 



Bemarks. This species is readily distinguished from any of the other Indian Cly- 

 peasters by the abruptly elevated dome-shaped region of the ambulacral petals. It is 

 perhaps nearer to C. Scillce, Desmoulins, from the Miocene of Corsica &c., than any 

 other form, but is very diflferent. In C. profundus the petals are shorter and further 

 removed from the margin, the elevated abactinal dome more prominent and abrupt, the 

 margin much thinner, with its contour less indented in the interradia; and finally the 



