OF WESTERN SIND. 57 



or 30 pairs of pores in the anterior zone, and 32 in the posterior ; and there are 38 or 

 39 pairs of pores in the zones of the postero-lateral ambulacra. The extrapetalous 

 continuation of the zones consists of single pores, rather widely spaced, in consequence of 

 the height of the extrapetalous ambulacral plates. Close to the peristome the pores are 

 nearer together, and there is some irregularity in their serial arrangement, and two or 

 three supplementary pores are present, thus forming a very indistinct and rudimentary , 

 phyllode. The interporiferous areas are flush with the surface of the test, but appear 

 very faintly convex in consequence of the slight depression of the poriferous zones. 

 The postero-lateral interradial areas are slightly prominent close to the apical 

 disk. 



The ornamentation of the interradial areas and that of the poriferous zones are simi- 

 lar, and consist of very small tubercles equidistantly spaced, and sunken in deep scrobi- 

 cules, the intermediate space being granular and with a tendency to become confluent 

 immediately round the scrobicule, the intermediate granules remaining more distinct. 

 On the abactinal portion of the test the intermediate granular spaces are usually greater 

 than the breadth of the scrobicules. In the interporiferous areas the tubercles are 

 slightly smaller and more crowded, and also just below the ambitus. On the actinal 

 surface the tubercles are larger than elsewhere, the scrobicules wider, and the inter- 

 mediate space is reduced to seldom more than a single granular ring, and which becomes 

 more or less confluent. There is an indistinctly defined, subconfluently granular, 

 median band, devoid of tubercles, extending between the peristome and the periproct. 



The peristome is large, slightly excentric in front, and more central than the apical 

 system, transversely elliptical, the breadth being y inch, and the shorter diameter ^ 

 inch, with the lateral apses acutely angular. The peristomial wall is closely granular, 

 and there is no development of bourrelets. The terminal portions of the ambulacral 

 areas which form the incipient phyllodes are very faintly sunken. 



The periproct is large, elliptical, placed longitudinally and inframarginal, sloping 

 up slightly from the actinal surface, and overarched by the posterior rostration of the 

 odd interradium. The length is -^q inch, and the breadth 2% inch. 



Dimensions. Length of the specimen 1^ inch, breadth 1 inch, height ^ inch. 



Distance of apical system from posterior edge -^g inch. 



Locality. East of Kandaira in the Vero plain, Eanikot series. Survey-number 



G226 

 155- 



Remarks. This is more nearly related to Plesiolampas elongata, Duncan and 

 Sladen*, than to any other member of the genus. It is distinguished from that orm 

 by the more elongate and anteriorly more contracted test, by its more level abactinal 

 surface and less gibbous posterior rostration, by its much wider, more petaloid, more 

 highly developed, and diff'erently proportioned ambulacra, by its more actinally placed 

 periproct, and finally by its more widely spaced tuberculation. Thgouh thus well 

 marked specifically, there is no doubt of this form being the representative of the Infra- 

 Trap species in the Eanikot strata. 



* Part i. page 10. 



