100 PEOF. P. M. Duncan's eevision of the 



Genus AEACHNiOPLETJims, Duncan <Sf Sladen, 1882, Pal. Ind. 

 ser. xiv., Foss. Fcli. W. Sind, p. 42. 



Test depressed, tumid at the circular ambitus, rising but 

 slightly abactinally. Epistroma well developed. Apical system 

 large, defective. 



Ambulacra narrow ; pairs of pores in slight arcs, penetrating 

 ridges which are continuous with radiating costse coming from 

 the scrobicular circle o£ the raised, small, perforate, crenulate 

 tubercles of the interporiferous area. Tubercles of both areas 

 in two vertical rows, each on a raised scrobicule from which 

 radiate costse, and the ends of these are surrounded by a circle of 

 raised rib-like structure, carrying large granules. The circle gives 

 ofO radiating costge externally, some of which reach the circles of 

 the opposed row of tubercles and others pass to the poriferous 

 areas. Vertically the circles are more or less in apposition. 

 Plates and sutures visible between the raised ornamentation. 



Peristome small, deeply seated ; branchial incisions small. 



Fossil. Eocene : Asia (Sind). 



Grenus Oetholophtjs, Duncan, 1887, Quart. Journ. Geol. Soc. 

 vol. xliii. p. 414. 



Test small, low, more or less pentagonal in marginal outline, 

 subcorneal above the tumid ambitus. Epistroma well developed. 



Apical system wanting. Periproct small aud circular. 



Ambulacra half of the width of the iuterradia at the ambitus, 

 straight, with slightly sunken poriferous zones ; pairs in ill-defined 

 triplets, nearly in straight series, appearing on the actinal flanks 

 of the costulation. Compound plates made up of a middle demi- 

 plate and an adoral aud aboral primary. A vertical row of small 

 imperforate, non-crenulated primary tubercles is close to the 

 poriferous zone in the interporiferous area ; and the space 

 between the rows is occupied by crowded, transverse, ridge-like 

 costse, passing from, the opposite tubercles and carrying small 

 secondaries. 



Interradia with two vertical rows of primary tubercles, of the 

 same size and shape as those of the ambulacra ; their scrobicules 

 raised, united with those placed actinally and dorsally by vertical, 

 straight costse, and with those of the opposite row by numerous 

 crowded, transverse, straight costse with small secondaries upon 

 them. 



