92 THE FOSSIL ECHINOIDEA 



The peristome is small, has a very decided f)osterior lip, which is on a lower plane 

 than the rest, and the opening is broader than long. The grooves of the ambulacra are 

 tolerably developed there. 



The lateral fasciole is narrow, and slopes forwards and downwards on the flanks, 

 close to the part of greatest bulging, so as to reach the front, below the ambitus, and 

 about midway between the mouth and the most projecting part of the anterior region 

 of the test. It crosses over in front of the peristome to become continuous with that 

 of the other side. Posteriorly this fasciole suddenly dips below the periproct in a down- 

 ward curve, and passes to the opposite side. It is slightly narrowest posteriorly. 



The incomplete peripetalous fasciole crosses the posterior interradial space, with 

 a faint backward curve on a line with the ends of the posterior ambulacra. It closes 

 their ends and then passes forwards, then curves suddenly downwards remote from the 

 antero-lateral ambulacra, to join the lateral fasciole. It is a narrow band, and is of the 

 same breadth as the hinder part of the lateral fasciole. 



Thus the antero-lateral ambulacra are remote from the fascioles. 



The test is profusely ornamented with a small tuberculation of diiferent sizes. 

 The smallest tubercles, situated within a raised margin in which they are sunken, are in 

 the posterior and postero-lateral interradials above. This kind is also seen below; 

 but the larger is observed below and especially on the plastron. In front of the 

 descending part of the peripetalous fasciole, the raised margins are formed by aggre- 

 gations of miliaries, and a larger and rounder scrobicule results with a well-deve- 

 loped boss and mamelon. This larger ornamentation is common over the front, except 

 along the line of the anterior odd ambulacrum, and it is very decided inferiorly and near 

 the peristome. The posterior ambulacra actinally and at the edge of the plastron have 

 an ornamentation of circular minute pits. 



Remarks. This species presents some resemblance to P. Desori, Cotteau, which is 

 perhaps its nearest ally ; but it differs from the Pyrenean species by its more elliptical 

 form and its relatively greater disproportion of length to breadth. The test of the 

 Sindian specimen is comparatively less high, and the truncation of the posterior extre- 

 mity slopes downwards and outwards from the dorsal area. The structure of the 

 antero-lateral ambulacra separates the form from Agassizia. 



Length 1 inch, breadth -^^ inch, height xq inch. 



Locality. North-east of Petiani, Ranikot series. Survey-number G -fff • 



Illustrations of the Species in Plate XIX. 

 Fig. 1. View from above : natural size. 



2. Actinal surface : natural size. 



3. Side view: natural size. 



4. Posterior view : natural size. 



5. Part of the odd anterior ambulacrum and ornamentation : magnified. 



6. Part of an antero-lateral ambulacrum : magnified. 



