U FAUNA OE BALUOHISTlN. 



areas nearly as broad as the interambulacral ones, poriferous zones a little undulat- 

 ing, composed of small pairs arranged in horizontal non-conjugated pores. Two rows 

 of rather large tubercles, the same size on both the ambulacral and interambulacral 

 areas. Mammillary eminence large, rounded, iniperforate, boss low, depressed, 

 crenulated, surrounded by an incomplete scrobicular circle of small granules, a few 

 isolated granules in the miliary zones. Peristome large, round, with ten short inci- 

 sions on the lower end of the five interambulacral areas. 



Locality and stratigrapMcal position. — D^s Valley, horizon 2. 



Remarks. — It is to be regretted that the specimen is too ill preserved to allow 

 a specific determination ; and considering the minute differences on which the 

 numerous species belonging to this genus are founded, it would be rash to identify 

 a specimen of which hardly more than the generic features can be ascertained. 



Subfamily: ECHINIDiE, Wright. 



PEOTEOHINUS, gen. nov. 



Test thin, large, circular in shape ; upper surface highly inflated, conical ; 

 lower surface flat, slightly pulvinated at the margin. 



Apical disc not very large, pentagonal ; genital plates perforated by large 

 holes ; anal opening comparatively small. 



Ambulacral areas less than half the breadth of the interambulacral ones, 

 slightly convex; interambulacral areas broad and probably slightly convex in 

 the centre. 



Poriferous zones straight, rather narrow ; pores small, rounded ; each ambulacral 

 plate carrying three pairs of pores, internal pair composed of minute holes ; in the 

 two external ones the holes are of much larger size, but equal in both pairs ; outer 

 pairs arranged in a zigzag line, at the internal angles of which are placed the minute 

 internal pair. Tubercles small, but uniform in size, imperforated, non-crenulated 

 arranged in vertical rows, which are most numerous at the ambitus and decrease in 

 number towards the apex and mouth, but remain more numerous on the lower than 

 on the upper surface ; two rows of tubercles on both ambulacral and interambu- 

 lacral areas reaching up to the apex. 



Periproct unknown. 



StratigrapMcal position. — Upper cretaceous series, Baluchistan. 



Bemarks.—^I hesitated for some time as to whether I should consider this 

 specimen as the type of a new genus or a species of the genus Psammechinusy 

 with which it shows the closest relationship both in general shape and the peculiar 

 arrangement of the pores. It differs, however, from all the known species belong- 

 ing to the genus JPsammechinus, Ag., in which genus the pores are all of equal 

 size and seemingly arranged in groups of three pairs on each ambulacral plate 

 obliquely Inclined in apical direction, as can be seen on Desor's plate XVIII, fig. 2a 



