OF WESTEEN SIND. 87 



Peristome eccentric in front, bilabiate, the inferior lip very prominent. 



Periproct oval, at the summit of the posterior extremity. 



Two fascioles, a peripetalous and a lateral, the latter diverging from near the 

 extremities of the anterior ambulacra and passing beneath the periproct. 



Tubercles perforate, crenulate, small and crowded on the abactinal surface, but 

 larger beneath the ambitus. The tubercles are not sunken in scrobicules, but are sur- 

 rounded by a small prominent disk. 



1. ScHizASTEE ALVEOLATUS, sp. nov. Plate XX, Figs. 10-14. 



There is a crushed specimen of Schizaster in the collection of Echinoidea from the 

 Eanikot series, which has much of the abactinal surface, flanks, and posterior parts 

 preserved, and which is deficient in the actinal region. It is of a brown colour ; and the 

 anterior odd ambulacrum and the left antero-lateral petal are filled with matrix and 

 more or less fragmentary small spines ; and the crushing has forced the apical end of 

 the anterior interambulacra downwards and has obliterated the apical system. Actinally, 

 the broken test is filled with brown matrix with Nummulites in it. At first sight the 

 form resembles Schizaster Newholdi, d'Archiac & Haime, as delineated in the ' Animaux 

 Fossiles de I'lnde;' but when compared with the types of that species, which are pre- 

 served in the Museum of the Geological Society, it will be noticed that there are specific 

 distinctions, especially in the relative length of the ambulacra and the number of pairs 

 of pores in them. Moreover the condition of the specimens of S. Newholdi really 

 prevents them from being of real value. It appears also that one of the three types 

 thus named is not of the same species, or possibly not of the same genus, as the others. 



The general shape is tumid, largest posteriorly, highest just behind the apical 

 system, sloping gradually in front and rapidly down the truncated posterior portion 

 to a sharp point of the convex and semi-keeled -plastron. The test has its greatest 

 breadth slightly behind the apical system. 



The apical system is slightly posterior ; its details are invisible. It is small and is 

 placed on a depressed area between the sharp suddenly-rising anterior keels, the broader 

 but still higher and less decided narrow ridges of the lateral interradials, and the slightly 

 narrower and more pronounced keel between the postero-lateral ambulacra. 



The anterior groove is large, deep, broad, excavated at the sides, which are high 

 within the fasciole, flat nearly on its floor; it becomes broader and shallower towards 

 the margin, which is moderately notched, and the groove persists slightly to the peri- 

 stome. The pairs of pores are placed partly on the sides of the groove and partly on 

 the floor — one pore (the outer and larger) being at the junction of the side and floor, 

 and the inner and smaller obliquely in front of the other and on the floor. Each pair 

 of pores, of which there are about 15 visible, is separated from its neighbours by a 

 broad costal elevation, and each pore is separated from its fellow by a broad tubercle. 

 The ornamentation of the floor of the groove is not seen, except in the form of a few 

 very minute granules near the apical region. 



The antero-lateral ambulacra are deep, slightly sinuous, rounded at the extremity 



n2 



