220 THE FOSSIL ECHINOIDEA 



Dimensions. The largest specimen measures 45 millim. in length, with greatest 

 breadth 46 millim. and height 29 millim. The antero-lateral petals are 21 millim. in 

 length, and the postero-lateral 18 millim.; the greatest breadth of the latter is 5 millim., 

 or a shade less. 



Localities. In the Khirthar series of strata : — i. Kois Hill, near Damaj, south of 



BulaKhan. Survey-number^. 



ii. Baili, west of Tong. Survey-number ^^. 



Illustrations of the Species in Plate XXXVII. 

 Fig. 7. Abactinal view of the test : natural size. 



8. Actinal view of the test : natural size. 



9. Longitudinal profile of the test : natural size. 



10. Odd anterior ambulacrum : magnified. 



11. Portion of one of the petaloid ambulacra: magnified. 



12. Apical disk: magnified. 



13. Abactinal view of an abnormal unsymmetrical test : natural size. 



14. Abactinal view of another abnornal unsymmetrical test : natural size. 



Genus SCHIZASTEE, Agassiz, 1836. 



(See anted,, p. 86, Part ii.) 



1. ScHiZASTER STMMETRicus, Buncan & Sladen. Plate XXXVII, Figs. 15-21. 



Test of small or medium size. Marginal contour oval, elongate, deeply indented 

 anteriorly by the anteal sulcus, rather more contracted towards the posterior extremity, 

 which is subrostrate, and more or less protuberant. The abactinal surface is not very 

 high, and when seen in longitudinal profile forms a well-arched curve, sloping gently 

 from the highest point, which is excentric posteriorly, to the anterior extremity, which 

 is thick and tumid. Immediately behind the highest point, the outline is slightly 

 curved, and is then abruptly truncate obliquely at a steep angle of inclination, which 

 extends to the ambitus, the area thus formed being more or less concave ; beneath 

 the ambitus the inferior margin of the posterior extremity is rounded off to merge into 

 the actinal surface, and is tumid and protuberant. The sides of the test are tumid, and 

 the actinal surface convex. 



The apical disk is almost subcentral, or very slightly excentric posteriorly. There 

 are only two generative pores, which are very large, and borne on hexagonal plates, 

 which correspond with the postero-lateral interradia. The anterior pair of generative 

 pores are aborted. The ocular plates are subpentagonal, and the posterior pair are 

 separated by the central madreporiform body. 



The odd anterior ambulacrum is situated in a wide and deeply excavated 

 groove, the floor of which is but slightly rounded, and is bounded by the high thin 

 ridge-like keels of the anterior interradia. The poriferous zones are placed in the 



