298 THE FOSSIL ECHINOIDEA 



2. CffiLOPLEUEUS SiNDBNSis, Dufican & Sladen. Plate XL VI, Figs. 3, 5, 6, 8, & 10, and 

 Plate XLVII, Figs. 1 & 2. 



The full-grown test is large, depressed, moderately tumid, and not high at the 

 ambitus, and decidedly conical towards the apex. The peristome is small and at a 

 higher level than the resting part of the test, the cuts are small but distinct, and the 

 under surface is rather flat. The apical disk is large and rather prominent, and the large 

 periproct is oblique. The basal plates are large, with a large circular or elongate pore 

 with or without a raised rim. The radials are also large and imperforate, there being 

 a median projection on the surface besides the ridges and furrows seen in other species. 

 The ambulacra are slightly raised above the level of the interradia, above the 

 ambitus, and are characterized by the large and somewhat irregular granulation of the 

 interporiferous areas, and by the absence of secondary and small primary tubercles. It 

 is very exceptional to see a small secondary in this part of the ambulacra, but they may 

 occasionally replace the normal granules on the larger and primary plates. The large 

 primaries with tubercles commence just above the ambitus, and at a higher level than 

 the great tubercles of the interradia. There is distinct granulation along the median 

 line of the ambulacrum at the ambitus and below, and some granulation just above the 

 pair of large tubercles. The pairs of pores are large, separated by some surface and 

 by a raised, arched, granulate costa. 



The interradia, slightly depressed between the ambulacra above the ambitus, are 

 limited there, on either side, by a raised vertical line of furrow, ridges, granules, and 

 small secondary tubercles, and these last become more numerous towards the ambitus. 

 This lateral granulation is comparatively uniform, and may resemble the ornamentation 

 of the interporiferotis areas close by. The tubercles at the ambitus are of the 

 same size as those of the ambulacra, and project as much, so that the circumference is 

 circular. There is a considerable large granulation amongst and around the great 

 tubercles of the interradia, and there are small secondaries at the median line as well 

 as near the poriferous zone close by. The crowding of these granules just abactinally 

 to the aboral large tubercles is very decided. 



The ornamentation of the disk is in some young specimens "very exaggerated. 



JHmensions. Breadth 34 millim. ; height 20 millim. Breadth 37 millim. ; height 

 22 millim. A half-grown specimen: breadth 26 millim.; height 16 millim. 



Locality/. Gaj or Miocene series of Sind. Tandra Rahim Khan, west of Sehwan ; 

 Naig Nai valley, three miles S.E. of Tong. Survey numbers G ^i^, G ^^, G ^o"- 



Illustrations of the Species in Plate XLVI. 



Fig. 3. The test ; natural size. 



5. Another test. 



6. The apical disk : magnified. 



10. The abactinal part of an ambulacrum : magnified. 



Illustrations of the Species in Plate XLVH. 



Fig. 1. The test, from above, 



2. A radial plate: magnified. 



