OF WESTERN SIND. 117 



median line of the interambulacral area is not naked. Eight to ten pairs of pores stand 

 opposite two' of 'the interambulacral plates. 



Peristome very wide, equal in diameter to one half of the diameter of the test, 

 circular or subdecagorial in outline, rather deeply indented by wide, well-developed 

 mouth-slits. The peristomial margin of the ambulacral area is very broad and convex 

 towards the mouth, with a graceful incurving at the median line. The margin of the 

 interambulacral areas is comparatively straight between the limits of the slits, slightly 

 convex in the median portion, and faintly. incurved on either side adjacent to the sharp 

 angular prominence formed by the slit. The margins of the slit are thickened and 

 turned backward. 



Apical disk wanting. The vacant space is of moderate size, nearly equal to one 

 third of the diameter of the test. 



Bemarks. Although this form is very depressed, and scarcely so turban-shaped as 

 a typical Cyphosoma, the slightly sinuous poriferous zones, the large primary tubercles, 

 and the wide peristome all warrant its inclusion in that genus. The species is distin- 

 guished from any with which we are acquainted by the position of the primary tubercles 

 on the interambulacral plates, and by the accompanying pair of obliquely-placed 

 secondaries, together with the large and well-characterized peristome. 



Dimensions. 



millim. 



Diameter of the test 26-5 



Height of the test 10 



Diameter of peristome 13"2 



Diameter of apical disk 9 



Locality. Khirthar series of strata. Probably from the Lower Nummulitic Lime- 

 stone : picked up in the infra-Nummulitic area. Hills under Jakhmari Peak, Laki 

 range, west of Amri. Survey-number ^^. 



Illustrations of the Species in Plate XXII. 



Fig. 8. Profile view of the test : natural size. 



9. Actinal view of the test, showing peristome : natural size. 

 10. Ambulacral and interambulacral plates : magnified. 



2. Cyphosoma undatum, Duncan & Sladen. Plate XXII, Figs. 11 & 12. 



There is a test in the Khirthar series of a rather large species of Echinoid which 

 we refer to this genus ; but unfortunately the specimen is so badly preserved, and the 

 greater portion of the detail so obscurely masked by a thin layer of matrix, that a 

 complete description is impossible. The following particulars are all that can be 

 furnished : — 



