326 THE FOSSIL ECHINOIDEA 



round and the outer much larger and pyriform, and the pairs are united by a very 

 faint conjugating furrow. The costse intervening between successive pairs are low and 

 rather narrow, and are ornamented with three small and well-spaced scrobiculated 

 tubercles, which do not come upon the part that separates the large outer pores, 

 where the costa is very narrow. The broadest part of the poriferous zone is 3 millim., 

 and is very nearly as wide as the interporiferous area at that place. The widest part 

 of the interporiferous area is midway between the extremities, where it measures 4'25 

 millim. The odd anterior petal is similar in all respects to the paired petals above 

 described, except that its outer extremity is rather fuller and more abruptly rounded. 

 The distance of the anterior pair of petals from the margin is rather less than two 

 thirds of their length, and the distance of the posterior pair is rather greater. 



The interradial areas are very faintly tumid or subcarinate on the inner half of 

 the abactinal surface. Their ornamentation consists of very small primary scrobiculated 

 tubercles, the intermediate spaces, which are covered with small uniform granules, 

 being usually rather greater than the diameter of the scrobicules. The ornamentation 

 of the interporiferous area is similar, but the scrobicules are more numerous and more 

 closely placed, and there is a general tendency to confluence in the intermediate 

 granulation. 



The actinal surface is perfectly plane, being abruptly rounded but not impressed 

 at the peristome, which is small, circular, and subcentral. The ambulacra are in 

 rather deep well-defined grooves, which extend nearly to the margin. 



The periproct is small and circular, and its distance from the margin is less than 

 its own diameter, 



Bemarks. This species is distinct from its congeners and other Indian forms by its 

 great depression, by its marginal contour, by the form of its petals, and by the flat and 

 unimpressed actinal surface. It comes nearer, perhaps, to C. placunarius (Lam.), 

 Agassiz (C. humile, Klein, pars), than to any other form, but is much more depressed, 

 and with the abactinal surface more conical and pointed at the apex, with the margin 

 more uniformly rounded and with no reentering curvatures, and with the petals more 

 widely open at the extremity. 



Dimensions. Length of the test 79 millim., breadth 72 millim., height 13 millim. 



Localities. In the Gaj series of strata :— 



i. Scarp of the M61 Plateau, west of Kund (the same scarp as G \^). Survey- 

 number G^i^^^. 



ii. Scarp at Kupo-jo-lak, or pass on the M61 range, west of Shah-beg (same 

 locality as G ^2°). Survey-number G^^^. 



iii. Four miles west of Beynlr Hill. Survey-number G ^2°-. 



iv. Gandak Hill, near Thado. Survey-number G\^. 



V. Hill near Giaibi, on the Baran River, south-east of Tonff. Survev-number 



Illustrations of the Species in Plate L. 

 Fig. 10. Abactinal view of the test: natural size. 

 11. Actinal view of the same : natural size. 



