OF WESTERN SIND. 353 



smaller near the margin and the boss is on one side of the flat scrobicule. The 

 ornamentation is spaall and in more or less parallel lines near the ambitus and above. 

 The lateral interradia come in contact with the peristome by means of a narrow 

 process. 



The posterior interradium is narrow and rounded from side to side on the dorsum, 

 but there is no prominent keel there. 



On the actinal surface the interradium presents an exceedingly long plate .1, which 

 has a narrow, tumid, and highly granular posterior mouth-lip in front and a long narrow 

 process behind. This plate 1 is bounded, on either side, by the three plates of the 

 posterior ambulacra, nearest the peristome, the pointed posterior end being on a level 

 with the termination of the first half of the third plate on either side. The plate is 

 very slightly raised and has the simple granular and distant ornamentation of the broad 

 ambulacra on either side. The sternum is small and keeled posteriorly, and generally 

 rounded ; it is closely and minutely tuberculate and granular, and is limited on either 

 side by the broad ambulacra, and behind by the subanal fasciole and the episternum. 

 One plate on either side is posterior and higher than the episternum, and then comes 

 the periproct ; this part when well preserved is in a broad and deep hollow, and the 

 surface of the subanal plates is smooth. 



There are evidently three types of this species, which are of racial value and no 

 more — the normal, the broad, and the long. 



The amount of structural difference is not specific, nor is it constant. The following 

 differences have been noticed : — The presence of more large pairs of pores within the 

 fasciole, and the greater breadth and area of this posteriorly ; the indistinctness of 

 the peripetalous fasciole in front, and the number of the great sunken tubercles. 



Measurements of specimens of Breynia carinata, d'Arch., from various localities 

 in the Gaj series : — 



a. Length 70 mm. Breadth 64 mm. Height 31 mm. 



j3. „ 66 mm. „ 52 mm. „ 26 mm. 



Locality, a. Hills about two miles north of Kadeji. Survey-number G \\^. 



3. Cliff-section of Kadeji gorge, thirty miles E.N.E. of Karachi. Survey 

 number G ^2^. 



Length 51 mm. Breadth 46 mm. Height 20 mm. 



Locality. About three miles S.E. of Tong. Survey-number G ^i-^. 



Length 67 mm. Breadth 53 mm. Height 27 mm. 



Locality. Ten miles N. of Shah-beg. Survey-number G ^^i-. 



Length 62 mm. Breadth 48 mm. Height 24 mm. 



This form has a decided roof-shaped keel in the odd interradium dorsally. 

 Length 54 mm. Breadth 45 mm. Height 23 mm. 



„ 52 mm. „ 42 mm. „ 22 mm. 



Locality. Hills east of Thana Shah-beg. Survey-number G ^. 



Length 50 mm. Breadth 38 mm. Height 24 mm. 



„ 46 mm. „ 36 mm. „ 22 mm. 



„ 45 mm. „ 34 mm. „ 21 mm. 



„ 37 mm. „ 27 mm. „ 16 mm. 



3b 



