OF WESTERN SIND. 261 



poriferous zone. The postero-lateral ambulacra are tumid, rather longer than the 

 others, and broader ; they are petaloid, and tend to close by the approach of the ends 

 of the poriferous zones, of which the posterior is the shortest. The peristome is narrow 

 and pentagonal, the anterior bourrelets being well developed, and the phyllodes are 

 rather petaloid. The tuberculation is very small and crowded on the actinal surface, 

 and is larger abactinally. 



Dimensions. Length 71 millim., breadth 60millim., height 20 millim. 



Relational dimensions. Length 1, to breadth 0"84, to height 0"28. 



Locality. Nari series, Oligocene of Sind. Near the base of the group, near Radak, 

 ten miles S.S.E. of Jhangara. Survey-number G-7^-. 



Illustration of the Species in Plate XL. 

 Fig. 10. The abactinal surface. 



There are many specimens of a species of Echinolampas in the collection from the 

 Nari series which may be associated with Echinolampas discoideus, d'Archiac. The 

 species is a very variable one and difficult to define ; and, indeed, all the species of the 

 genus Echinolampas from the Nari series have a facies in common, whatever may be 

 their size. 



4. Echinolampas discoideus, d'Archiac. Plate XLI, Figs. 1 & 2. 



We give a summary of the description of the species by its authors, and then 

 remark on the definition afterwards. 



Test subcircular, a little longer than broad ; no angular tuberosities on sides. 

 Margin rounded. Slight projection above the anus. Apical summit slightly project- 

 ing at the anterior two fifths of the great diameter. Four genital pores rather small. 



Petals long, flat, almost as open as in Conoclypeus, rather broad, and almost 

 unequal amongst themselves in this respect. The two posterior are broader than the 

 antero-lateral, and the odd ambulacrum is the narrowest. The antero- and postero- 

 lateral ambulacra very slightly bent at the apex. 



Poriferous zones rather broad, subcostulate, almost equal in the same ambulacrum. 

 Interradial areas unequal ; measured half way down the petals, the posterior is the 

 broadest and the anterior are the narrowest, but near the apex these last are broader 

 than the lateral. 



Actinal surface subplane, slightly sunken in the middle. 



Peristome nearly central ; buccal tuberosities moderately pronounced, 



Periproct inframarginal, small, and tolerably regularly elliptical in shape. 



Tubercles small, close, especially at the margin, slightly unequal, principally on 

 the ambulacra. Those near the peristome are larger than the others. 



Length 7'6 centimetres, breadth 7-3, height 3-3. 



Length 7 „ breadth 1 , height 2-8. 



The types chosen by d'Archiac (described in ' Les Animaux fossiles de ITnde,' 

 p. 209) were well crushed from above downwards ; and his drawing shows that the 

 posterior half of the actinal part of the test is more tumid than the anterior ; but 



