OF WESTERN SIND. 283 



ambulacra (or, more exactly, the ambulacra may be estimated at three tenths the 

 width of the interambulacra). The width of the interambulacral plates is remarkable, 

 that of the large plates near the ambitus being proportional to their own length 

 (i. e. height) as 1 : 0-55. In a similar-sized example of C. opipara, nobis, the plates occu- 

 pying the same position have their width proportional to their length as 1 : 0"66. The 

 primary tubercles are rather small, perforate, but not crenulate ; mam el on s mode- 

 rately prominent, somewhat button-shaped, and with a well-incised neck. The 

 scrobicules are transversely oval and extend close to the ad- and aboral margins of the 

 plate. The scrobicular ring is complete, but the granules at the ad- and aboral 

 margins are pushed so close to the edge of the plate as to appear to be slightly cut 

 away. The space which intervenes between the scrobicular ring and the poriferous 

 zone at the ambitus is a little more than half the space which intervenes between the 

 scrobicular ring and the median suture, and is about equal to the width of half the 

 interporiferous area. The scrobicular ring is composed of 22 to 24 small miliary 

 tubercles, indistinctly mammillated and rather closely placed ; the space on the pori- 

 ferous side of the plate on the one hand and the miliary zone on the other being 

 occupied by small miliary granules which diminish in size as they recede from the 

 scrobicular ring, the granules or miliary tubercles composing the latter not being very 

 much larger than the series of miliaries immediately external to them. This cir- 

 cumstance goes far to obliterate the prominence of the scrobicular ring, and imparts a 

 characteristic facies to the form. The miliary granulation on the whole is well spaced ; 

 and indistinct traces of superficial channelling, forming Jines of granules in single file, 

 which pass from one scrobicule to the next adjacent, may be discerned here and there. 

 The sutures of the plates are rather deeply incised, especially where the horizontal 

 sutures fall into the median suture at the angles of the plates, and suggest more or less 

 forcibly a Goniocidarid facies in this respect. 



Dimensions. In the better-preserved fragment the width of the interambulacral 

 area at the ambitus is 20 millim. ; the length of the whole fragment 32 millim., which 

 does not represent the full height of the test. 



Localities. In the Gaj series of strata : — 



i. Entering the hills on the road from Jangri to Bula Khan's Thana. Survey- 

 number G^a^. 



ii. Siimbak pass, east side ; three or four miles north of the darwat or gorge of 

 the Baran Eiver. Survey-number G -3-5°. 



Illustrations of the Species in Plate XLIV. 



Fig. 9. A fragment of the test : natural size. 



10. Ambulacral plates : magnified. 



11, Interambulacral plate : magnified. 



3. CiDAKis, detached spines of several species. Plate XLV. 



There are in the Gaj collection a large number of spines, probably belonging to 

 several species of Cidaris. Of these it may be said that the majority have a striking 



2q2 



