226 THE FOSSIL ECHINOIDEA 



(The matrix, which is arenaceous and of a grey colour, is altogether different 

 from that of any of the large series of specimens obtained from this locality ; and it 

 appears almost unquestionable that the assignment of this specimen to the Khirthar 

 series results from an accident in labelling.) 



Illustrations of the Species in Plate XXXV. 



Fig. 1, Abactinal view of the test : natural size. 



2. Longitudinal profile of the test : natural size. 



3. Ornamentation of the plates in the lateral interradium : magnified. . 



Genus BRISSOPATAGUS, Cotteau, 1863. 



Test of medium size, oval, moderately inflated above, almost flat beneath, sub- 

 carinate in the posterior region. 



Ambulacral summit excentric in front. Anterior sulcus not defined on the dorsal 

 surface, but tolerably deep near the ambitus. Anterior pair of petals short, widely 

 divergent, curved, situated in wide subcircular depressions, which thin out anteriorly. 

 Posterior ambulacra more elongate, almost straight, subtending an acute angle. 



Peristome excentric in front, semicircular. 



Periproct elliptical, opening on the posterior extremity. 



Fascicles % 



This remarkable genus, which was established by Cotteau for the reception of 

 two species — one from the Nummulitic strata of Biarritz and the other from Java, is 

 especially characterized by the peculiar curvature of the anterior pair of petals, and by 

 their position in wide, subcircular, shallow depressions or concavities of the test. A 

 third species has subsequently been described by Dames from the neighbourhood of 

 Verona. 



The fossil from the Khirthar series of strata of Sind, which we are about to notice, 

 accords in all points with the generic diagnosis defined by Cotteau, but unfortunately 

 our example has suffered great damage from weather action, and the specific description 

 which we are able to furnish is consequently in some respects imperfect. 



1. Bkissopatagus Sindbnsis, Duncan & Sladen. Plate XXXVIII, Figs. 19-21. 



Test of medium size, elongate ; marginal contour a subpyriform heart-shape, faintly 

 indented anteriorly, the greatest breadth across a line lying in front of the centre, thence 

 tapering considerably to the subrostrate posterior extremity. The greatest breadth is 

 about four fifths of the length, or in the proportion of 0'79 : 1. Abactinal surface 

 subdepressed, fiatly convex, arching from the rather abruptly rounded margins. The 

 odd posterior interradium is tumidly subcarinate, and the greatest height of the test 

 lies at a point midway between the outer extremities of the posterior petals and verti- 

 cally over the culminating point of the actinal plastron, the prominence of the latter 

 greatly augmenting the measurement, the height being here proportional to the length 

 as 0-45 : 1. 



The apical disk is excentric in front, its distance from the anterior margin being 



