OF WESTEEN SIND. 199 



petals in wide and somewhat deeper grooves, whose size and character is emphasized by 

 the remarkable carination of the anterior interradia, — a sharply prominent median keel 

 being developed, from which the test slopes steeply down to the groove on either side ; 

 whilst the individual plates of the interradium are also subtubercularly prominent 

 along this line and add considerably to the remarkable facies of the test. The lateral 

 interradia show the same feature of carination along their median line, but to a less 

 degree. The odd posterior interradium is decidedly convex and carinate, and its slopes 

 form a convex curve. The carinations of the interradia die out as they approach the 

 apex, and the apical disk is consequently only very slightly depressed below the general 

 level. 



The course of the antero-lateral petals is almost straight from the apex towards 

 the margin, and the outer extremity of the groove is very shallow and apparently lQ- 

 defined. The divergence of this pair of petals is very wide, the angle subtended being 

 about H6°-120°. The postero-lateral petals are comparatively long, measuring alpout 

 14 millim., whilst the anterior pair are about 17 millim. in length ; the general 

 characters in both being similar. 



In the odd anterior ambulacrum the obliquely placed pairs of pores are rather 

 vdde apart, the inner pore being somewhat comma-shaped, the outer one larger, and 

 separated from its companion by a large and partly overhanging lip-like tubercle or 

 granule ; the whole floor of the groove is covered with small crowded granules. In the 

 antero-lateral petals both the inner and the outer pores are long and slit-like and rather 

 wide apart ; the pairs are separated by a very broad space or band, which does not 

 develop a ridge-like keel, but bears usually two rows of small uniform granules, the suture 

 of the plates being visible between the two series, and there is a faint trace of a feebly 

 raised rim encircling the pore-slit. Near to the apex the inner series of pores are 

 almost aborted. 



The structure of the apical disk is interesting. The anterior pair and the posterior 

 pair of generative pores are equidistantly placed, and the posterior pair of ocular pores 

 are placed directly beneath the latter, being also at an equal distance apart, and they are 

 separated by an extension of the median madreporiform body ; there is thus a regular 

 line of three pores on either side of the median line. The anterior pair of ocular pores 

 are placed external to the anterior generative pores, with which they form a transverse 

 line of four pores. The odd anterior ocular pore is slightly in front of the anterior 

 generative pores. 



Traces of a single narrow peripetalous fasciole are present. There was no lateral 

 fasciole. 



The ornamentation of the test is comparatively large, isolated, and remarkably 

 well defined. 



Dimensions. We are unfortunately unable to give the usual measurements of the 

 test. The following dimensions may serve as a guide. From the centre of the apical 

 disk to the margin, along the median line of the anterior interradium, about 25 millim. ; 

 from the centre of the apical disk to the margin, along the median line of the postero- 

 lateral interradium, about 30 millim. 



2d2 



