OF WESTERN SIND. 239 



anterior ambulacrum is scarcely discernible ; it is flush with the test near the apex, the 



groove being developed only near the margin, and the pores are quite microscopic. 



The antero-lateral petals are long and widely divergent, and scarcely so petaloid as 



frequent in this genus. Their course has a slightly sigmoid tendency, with a slight 



curve forwards at the outer extremity, the flexure of the posterior zone of the petal 



being much greater than that of the anterior zone. The postero-lateral petals are 



longer than the anterior pair and a shade broader ; they are rather widely divergent 



for posterior petals, and have also a slight sigmoid curvature. Excepting at the apical 



extremity, where the convergence is great, and the petal is very attenuated, the zones 



to a certain extent have the appearance of running parallel to one another, the 



posterior zone curving, however, conspicuously towards its companion at the outer 



extremity. The poriferous zones are broad in the anterior and posterior petals alike ; 



the pores are transversely oval, wide apart, and connected by a conjugating furrow, 



and the divisional septa are ornamented with a single line of minute miliary granules. 



The interporiferous area is equal in width to the poriferous zone midway between the 



extremities, and appears to have been ornamented with a few widely spaced miliary 



granules with a rather larger one than the rest opposite each of the divisional septa, 



and sometimes two. The areas of the paired ambulacral petals are slightly sunken in 



shallow, widely expanded, depressions of the test, which are so wide and shallow that 



they are in no sense grooves; and their presence imparts a certain appearance of 



tumidity to the interradial areas. 



The large primary tubercles within the fascicle on the abactinal surface are rather 

 numerous, prominent, and on conical bosses ; they are unequal in size, the largest 

 being near to the margin of the petal, and they do not present the appearance of 

 definite arrangement very conspicuously ; their mamelons are very small and perforate, 

 and the crenulation is distinct ; the scrobicules are large, circular, and very slightly 

 sunken ; and the intervening portions of the plates are occupied with a minute but 

 definite miliary granulation, amongst which a few very small perforated tubercles are 

 placed. In the neighbourhood of the margin the perforated tubercles are small, 

 uniform, regular, and numerous, and their scrobicules are separated only by a single 

 circlet of very small miliary granules, and even this is sometimes incomplete. On the 

 actinal surface the primary tubercles are large, and though apparently well spaced, 

 there were probably very few miliary granules present in consequence of the crowding 

 and overlapping of the large disk-like scrobicules, one margin of which is more or less 

 prominent. 



Both peristome and periproct unfortunately are destroyed; the position of the 

 former was very excentric in front, and there appears rather considerable depression 

 around the anterior margin of the aperture, and especially defined in the three anterior 

 ambulacral areas. 



The peripetalous fascicle is a very narrow band, running close to the outer margin 

 of the abactinal surface, and only a little above the ambitus on the anterior half of the 

 test ; in the posterior column of the lateral interradia it gradually leaves the margin 

 and encroaches more on the abactinal surface, passing close to the extremity of the 



