gejsteba atsd groups of the echinoidea. 99 



a simple deepening along tHe line of suture, for the furrow is broad. 

 In every specimen there is more of the radiation of the miliaries 

 from a tubercle than is given in any drawing hitherto published, 

 and the miliaries are much more crowded and irregular in sbape 

 than has been figured. 



The raised nature of the epistromal ornamentation is seen 

 around the spaces which occur along the transverse and. the 

 vertical sutures in well-preserved British specimens ; it gives a 

 very Temnopleurine appearance to the test. The figure given 

 by Cotteau, Pal. Franc, vol. vii. pi. 1128, figs. 16-22, of a. ru- 

 gosus shows the tubercles with, four or five costse projecting 

 adorally instead of one, and recalls OpecMnus, Desor. The 

 sutures in this species are partly, but well gTOoved near the 

 angles of plates. 



Genus Dicttopleueus, Duncan Sf Sladen, 1882, Fal. Ind. ser. xiv., 

 Foss. Ech. W. Sind, p. 38. 



Test small, hemispherical above, slightly concave actinally, 

 more or less turban-shaped. Epistroma well developed. 



Apical system : periproct oblique, elongate, elliptical, with a 

 raised edge ; basals unequal, with depressions between the fora- 

 mina and the ring ; radial plates large, some enter the narrow 

 ring. 



Ambulacra narrow, straight, pairs of pores in straight series ; 

 tubercles of the interporiferous area very small, in two vertical 

 rows close to the poriferous zones, indistinctly crenulate and 

 perforate, united by a zigzag of raised broad or narrow ridges. 

 Each tubercle is connected with two of the opposed row, and 

 with the tubercles placed above and below, by a raised rib-like 

 ornamentation. 



Interradia broad, with two vertical rows of primaries resembling 

 those of the ambulacra, but more distinctly perforate and crenu- 

 lated, united witb tbose of tbe opposed row by abroad or narrow 

 oblique or longitudinal, raised, granulated or not, series of costge, 

 and with the tubercle immediately above and below by means 

 of a narrow vertical costa; the tubercles are raised above the 

 common level. The sutural lines between the plates of both 

 areas are visible, and are plain and not sunken. 



Peristome small, and the branchial incisions also. 

 Fossil. Eocene: Asia ("W. Sind), Africa (Egypt). 



7* 



