32 FAUNA OF BALUCHISTIN. 



however, inclined to think that, owing to the deep shades, Hubert's figure is a little 

 deceptive, and the anal opening is really nearer to the posterior margin than it 

 appears. 



Now, we must consider the question whether these two differences, if they 

 really do exist, and are /not, as I feel inclined to think, accidental features of the 

 drawings, are of such importance as to justify a specific separation of the two forms. 

 In my opinion they are not, since, if this view were taken, an otherwise well preserved 

 specimen, which is perhaps rather damaged at the posterior side, and thus does 

 not allow the correct position of the anal opening being fixed, nor to ascertain 

 whether the large tubercles exist all over the posterior part of the lower 

 surface, could not be identified, one would be always left in doubt whether such 

 specimens belonged to H. pyrenaicus or to the new species, whatever it may be called, 

 from Baluchistdn. To reduce specific differences to such minute details would, in 

 my opinion, be going too far, and would rather harm the true relationship of species 

 than benefit it. 



Hemipneustbs letmeriei, Hebert. PI. VII. fig. 2-2A. 



1875. Hemipneustes leymeriei, Hubert, Bull. Soc. Geo), de France, eer. iii, III. page 594, pi. XX. 



Dimensions of the single specimen. 



Length L =48 



Breadth b =47 



Height h . . . . ; =31 



h /^/> 



L 

 h^ 

 L 



^ =-64 



Only a single specimen of this species has come under examination, and even 

 this is damaged on the posterior side, inasmuch as the plates are partly broken off. 



The test is suborbicular, slightly truncated behind; the upper surface is 

 inflated, but the profile is a little unsymmetrical on account of the apex being 

 behind the centre ; anteriorly it slopes very gradually, while on the posterior side it 

 drops in a nearly vertical line. Sides slope slightly. Lower surface somewhat 

 convex on the plastron near the ambitus. The apical disc is small, not elon- 

 gated, and lies behind the centre, and being partly destroyed its details cannot be 

 observed, but it seems that there exist also four genital plates perforated by large 

 holes. 



The anteal sulcus begins with a scarcely perceptible depression near the 

 summit, which gradually deepens towards the ambitus, getting narrower at the same 

 time. The single ambulacrum which it lodged in the anteal sulcus, shows the same 

 features as in the other two species. 



The antero-lateral ambulacra are large, very long, reaching as far down as the 

 ambitus, and are strongly curved forwards ; they are composed of two very unequal 

 poriferous zones ; the anterior one is very narrow near the summit, but gradually 



