24 PAUNA OP BALTJCHISTlN. 



Genus : OLTPEOLAMPAS, Cotteau. 

 CiYPEOiAMPAS HELIOS, spec. nov. PI. V. fig. 3-3b, 4, 5.5A. 



Dimensions of three specimens. 



Length L =61 58 56 



Breadth b =48 50 4? 



Height h =42 40 37 



J* ....... =-88 -86 -84 



L 



A =-68 -68 -66 



L 



The thick test is oval, slightly broader behind than before, where it is a little 

 contracted ; the upper surface is tumid ; the apex excentral and slightly forward ; 

 the longitudinal profile declines in a short curve on the anterior side, while it slopes 

 a little more on the posterior side ; the sides are inflated and rounded ; the lower 

 surface flat, slightly concave around the mouth. 



The excentral apical disc, which is star shaped, is composed of four genital 

 plates which are perforated by large holes and five ocular plates perforated by 

 minute holes ; the genital plates are very small, with the exception of the madre- 

 poriform plate, which is very large and completely fills the centre, nearly overlap- 

 ping the other plates ; the ocular plates are microscopical and hardly visible. 



The ambulacral areas flush with the test are broadly lanceolate, open, straight 

 and very uniform in their proportions; the posterior ambulacra slightly longer than 

 the others, the single ambulacrum and the anterior pair equidistant from each 

 other, but the posterior pair is slightly more distant from the anterior pair and 

 is placed more closely together. The number of pairs of pores in each zone is 

 nearly equal, varying from 64 to 66 ; the pores in the inner row are small and 

 round ; the outer pores are elongated and are joined to the former by fine horizontal 

 sutures. At the lower part of the petals the pores suiddenly become much smaller 

 and are set much wider apart as they pass round the border of the test and extend 

 to the peristome, where they increase again in size. The peristome is slightly 

 excentral and occupies a slight depression near the anterior border ; it is rather 

 large, pentagonal and surrounded by a large well developed floscelle. 



The buccal petals are only slightly concave, but rather broad and widely open 

 at their ends ; the poriferous zones are well developed and consist of numerous 

 small elongated pores in the outer row, and a smaller number of rounded pores in 

 the inner row which are connected by very shallow grooves. The single petal is 

 the shortest, the antero-lateral pair the longest. 



The interambulacra end in short rounded bourrelets which are covered 

 at the sides with an extremely delicate granulation and on the top with a few 

 larger tubercles. 



The small longitudinal periproct is situated just above the posterior margin, 

 but not visible from above, at the lower end of two obtuse, hardly visible keels, 

 which extend from the apical disc to the posterior margin. 



