GENEEA AND GROUPS OF THE ECHINOIDEA. 125 



late, imperforate tubercles in each interporiferous area near tlie 

 poriferous zones ; small tubercles or granules near them amongst 

 the pairs of pores. 



Interradia with two or more vertical rows of small crenulate 

 tubercles diminishing in number actinally. Miliaries numerous. 



Fossil. Eocene : W. Sind, Asia. 



G-enus tEolopneustes, Duncan and Sladen, 1882, Pal. Ind. 

 ser. siv., Foss. Fch. W. Sind, pt. ii. p. 47. 



Test large, tumid, subcircular or subpentagonal in outline, 

 subcorneal depressed abactinally, flat actinally, with a slightly 

 depressed peristome. Twice as broad as high. 



Apical system wanting. 



Ambulacra broad, more than half of the breadth of the inter- 

 radia at the ambitus, slightly prominent in contradistinction to the 

 interradia, which are sunken along their median lines. Poriferous 

 zone broad dorsally, narrow at the peristome ; abactinally the 

 pores are in almost horizontal arcs of five or six pairs, and are 

 very regularly and closely placed ; below the ambitus the number 

 of pairs in each arc diminishes, the arcs straighten vertically, 

 and the series of pairs become less oblique and almost uni- 

 serial, and are quite close to the peristome. The ambulacral 

 plates are nearly as high as the corresponding interradial 

 plates and are compound ; the composition of a plate halfway 

 between the peristome and the ambitus is a low broad adoral 

 primary plate, followed aborally by a large primary which 

 is low near the ambulacro-interradial suture and expanded 

 elsewhere, and comprises all the median sutural edge of the 

 compound plate except that adoral portion which belongs to 

 the small adoral primary component ; above the large primary 

 is a small demi-plate, and the aboral plate of the combiua- 

 tion is also a demi-plate, but is larger than the other, and has its 

 adoral suture convex towards the primary tubercle of the com- 

 pound plate. In some compound plates the low adoral primary 

 is replaced by a small low demi-plate, with its aboral suture convex 

 towards the primary tubercle ; and in these instances the compo- 

 sition of the plate is mainly that of Diadema. Close to the 

 peristome the adoral and aboral plates are low primaries. The 

 pairs of pores are close and round. Interporiferous areas with a 

 vertical row of small crenulate primary tubercles raised above the 

 test and large and small granules. 



