OF WESTERN SIND. 119 



Dimensions. 



millim. 



Diameter of the test 42 



Height of the test 17 



Relative proportion of the ambulacral to the interambulacral area, at their greatest 

 breadth, 42-4 per cent. 



Locality. Khirthar series of strata. Dharan Pass (east side), near Laki. From 

 the white limestones above the shales. Survey-number ^^. 



Illustrations of the Species in Plate XXII. 



Fig. 11. Outline of the profile contour of the test : natural size. 

 12. Ambulacral and interambulacral plates: magnified. 



Genus MICEOPSIS, Cotfeau, 1856. 



Test of moderate size, circular, subhemispherical or often more or less inflated, 

 concave beneath. 



Poriferous zones straight. Pores arranged in simple pairs in uniserial series. 



Primary tubercles in both series relatively small, delicate, and numerous, finely 

 crenulate, imperforate, and forming more or less regular vertical series. 



Peristome small and slightly indented. 



From the above diagnosis it will be seen that the differences which separate this 

 genus from Cyphosoma are individually those of degree only — the uniserial poriferous 

 zones, the small, delicate, and cofiiparatively more numerous primary tubercles, and the 

 small and slightly indented peristome being the characters upon which the division is 

 based. Although the value of these characters per se would appear small, their com- 

 bination produces a fades very different from that of an ordinary Cyphosoma. On this 

 account it seems convenient to retain the section, although its zoological validity might 

 well be contested, as P. de Loriol has already pointed out*. 



1. MicEOPSis VENUSTULA, Duncan & 8laden. Plate XXII, Figs. 1-7. 



The test is of moderate size, circular or subpentagonal in marginal contour, 

 depressed, height less than one half the diameter, regularly convex above, concave 

 beneath, and rather deeply impressed around the peristome, which is small ; margin 

 well rounded and tumid. 



Ambulacral areas narrow, less than one half the breadth of the interambulacral 

 area at the widest part, slightly prominent, the interporiferous area being somewhat 

 raised. Poriferous zones straight, pores arranged in simple series throughout, no 

 doubling present either at the apical or peristomial extremity. The pores of a pair are 

 separated by a slight granuliform eminence, and a faint costal ridge, appearing as lateral 

 prolongations of the granule, occurs on the aboral margin of the ambulacral plate, and 



* Descrip. Echin. tert. de la Suisse, p. 26 (Mem. Soc. Paleont. Suisse, vol. ii.). 



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