266 THE FOSSIL ECHINOIDEA 



poriferous zones are equal in length, and the breadth of the two combined is rather less 

 than that of the interporiferous area. The larger pores are of considerable dimensions ; 

 those which are at the distal end are subequal and nearly circular or elliptical in outline, 

 but the outer pores become more and more elongate and straight comma-shaped towards 

 the middle of the ambulacrum ; thence they become gradually smaller. .The inner 

 pores are more elliptical than circular in their outline, and are smaller than the others. 

 There is a very decided obliquity of the pairs of pores, which is produced by a 

 slope of the outer part of the ambulacral plate ; and the costa between the pairs of pores 

 is wide and short, and carries more than one row of minute miliaries arranged in rather 

 a confused manner. There is but little narrowing of the poriferous zones towards 

 their termination. This ambulacrum is the shortest and narrowest, and its length 

 is 52 raillim. and greatest breadth 11 millim. 



'i'he antero-lateral ambulacra are broader and longer than the anterior one ; the 

 poriferous zones become narrow towards their end, and the anterior, the shortest, has 

 its terminal pair of pores curved backwards ; it is the shorter by about five pairs. 

 Neither of the zones is much curved. The length is 56 millim., and the greatest 

 breadth 12 millim. 



The postero-lateral ambulacra are very long, 65 millim., and as broad as the antero- 

 lateral. There is slight difference in the length of the poriferous zones, vphich diminish 

 in breadth towards the end, and only a slight disposition to close. 



The ornamentation of the interporiferous areas is smaller than that of the inter- 

 radia, is not very close, and is rather transverse. The tubercles are small, sunken, and 

 separated by a vrell- developed raised area, which is minutely granular (Fig. 8). The 

 costse are broad, and have at least two rows of miliaries on them. 



The peristome, broadly-pentagonal, is slightly in front of the centre, and is surrounded 

 by the tumid actinal surface ; the breadth is greater than the length from before back- 

 wards, and the bourrelets are fairly developed. The phyllodes are not large, but there 

 is doubling of some pores. The posterior lip is the broadest and flattest. The 

 breadth is 12 millim. 



The periproct is on the upper and backward slope of the margin, is broader than 

 the peristome, and is an elongate ellipse with the anterior margin more curved than the 

 posterior. 



The ornamentation of the interradia, abactinally, resembles that of the inter- 

 poriferous areas, and it is slightly the larger. It increases steadily and gradually in size 

 from the margin to the peristome; the tubercles become larger, situated in deeper 

 scrobicules, and the intertubercular ornamentation becomes larger, wider, and more 

 distinct. The largest ornamentation is in the ambula-cra near the peristome, and on 

 the posterior lip a little remote from the mouth. In those localities the granular 

 ornamentation between the tubercles is wide. 



Dimensions. Length 117 millim., breadth 107 millim., height 64 millim. 



Eelative dimensions. Length 1, to breadth 0-91, to height 0-54. 



Locality. Nari series (Oligocene). Trak Hill, 17 miles S. of Bula Khan. Survey- 

 number G ^^. 



