170 THE FOSSIL ECHINOIDEA 



Loccdity. In the Khirthar series of strata : Eiver-section, east of Trak. Survey- 

 number ^. 



Illustrations of the Species in Plate XXX. 



Fig. 12. Abactinal view of the test : natural size. 



13. Actinal view of the test: natural size. 



14. Longitudinal profile of the test : natural size. 



15. Peristomial extremity of the left anterior ambulacrum : magnified. 



8. EcHiNOLAMPAS JUVENILIS, Dutican & Sladen. Plate XXX, Figs. 16-18. 



Test of small size. Marginal contour suboviform, well rounded in front, the 

 greatest breadth occurring in the posterior part of the lateral interradia, where the 

 test is slightly tumid ; from thence the outline contracts rather rapidly along the 

 prominent and well-marked rostration. The greatest breadth is proportional to the 

 length as 0'81 : 1. The dorsal surface is regularly convex, and the height is rather 

 less than one half the length. 



The apical disk corresponds with the summit of the test and is excentric in front, 

 the anterior and the posterior portions of the median longitudinal line being propor- 

 tional as 19 : 35 or as 1 : 2 approximately. Seen in longitudinal profile, the dorsal 

 convexity is of comparatively low elevation, the inclination of the anterior slope is very 

 slightly greater than that of the posterior, and the anterior margin is very thick, tumid, 

 and well rounded. The posterior slope passes with a well-rounded curve over the 

 posterior rostration. The transverse profile shows a faint tendency towards a subconoid 

 form in the outline of dorsal convexity, and the margins are thick and tumid. The 

 actinal surface is somewhat concave and most depressed along a transverse line passing 

 through the peristome. The surrounding actinal portions of the test are tumid, their 

 curvature merging iminterruptedly into that of the margins. 



The ambulacral petals are long, straight, and narrow, and present no expansion. 

 The posterior petals are the longest, and the odd anterior petal is slightly narrower 

 than the others. The poriferous zones are unequal ; the anterior zone of the posterior 

 petals and the posterior zone of the anterior petals being longer by 6-8 pairs of pores 

 than their companion zones in the respective petals. The pores are subequal ; the 

 inner pores round, and the outer pores also round or slightly oval transversely. The 

 pores are united by a faint groove, and the divisional septa develop midway a slight 

 granule-like prominence. The extrapetalous portion of the zone is flush with the 

 test, and its course is not marked by any channel or depression. 



The interporiferous areas are flush with the level of the test in the pfctaloid portipn 

 of the ambulacrum ; but there is a slightly tumid swelling of the area, faintly aflfecting 

 also the adjacent parts of the interradia, discernible in the marginal contour. In the 

 anterior interradial areas a slight tumidity is developed along the median line of the 

 actinal portion of the area. The lateral interradia are tumid marginally, especially in 

 the posterior column of the area; and the odd posterior interradium is very tumid and 



