18 EATJNA OF BALUCHISTAN, 



so well, that I think it would be a mistake to describe them under a new specific 

 name. Unfortunately in Cotteau's description nothing is mentioned about the 

 arrangement of the tubercles, nor the peculiar form of the pairs of pores. With 

 regard to the former, the figures of Echinoconus gigas are unquestionably not trust- 

 worthy, being apparently more or less diagrammatic. I am unable to say how far the 

 Baluchistan specimens agree with the original, but as regards the pairs of pores, an 

 enlargement of which is given on Cotteau's plate995, fig. 4, a marked difference 

 seems to exist, provided fig. 4 is drawn correctly ; it exhibits two pores separated 

 by a large rounded tubercle and surrounded by an elliptical filiform ridge, if I 

 correctly interpret the line which surrounds the pores. Now if only moderately 

 enlarged, the pairs of pores of the Baluchistdn form exhibit similar features, but 

 if looked at through a powerful magnifying lens, they show the peculiar arrangement 

 above described. Whether this may be regarded as a real difference between 

 the forms from Baluchistan and those from the Pyrenees must remain an 

 open question for the present. If so, the Baluchistan form must receive a new 

 name, although it should always be remembered that its closest relation is 

 Echino'conus gigas from the Pyrenees. But as this question cannot be decided 

 at present, I prefer identifying it with that form, considering that the general 

 shape of the test agrees so exceedingly well with it. 



Genus : HOLEOTTPUS, Desor. 



HOLBCTTPTJS BALTICHISTANBNSIS, SpeC. nOV. PI. III. fig. 3-3B. 



Dimensions. 



Length L =31 mm, 38 mm. 



Breadth b = 31 „ 38 , 



Height h = 20 „ ? 



The test is circular, length and breadth being the same ; the upper surface is 

 moderately inflated, regularly rounded in all directions ; profile line oval, ambitus 

 rounded, lower surface pulvinated. 



The apical disc is small and not distinctly visible, but the madreporiform plate 

 is large, completely filling the whole centre. 



The ambulacral areas are broad, about half the breadth of the interambulacral 

 areas at the ambitus : the poriferous zones are flush with the test, very narrow and 

 filiform ; they arecomposed of minute round pores, which are arranged in oblique 

 pairs. 



Peristome central, invisible in all the specimens, but apparently not very large. 



Periproct very large, oval and pointed at each end ; situated on the lower 

 surface and nearly filling the whole space between mouth and ambitus, so that there 

 exists only a very narrow bridge between its anterior end and the mouth. 



The ornamentation consists of very small perforate tubercles, on a non- 

 crenulated boss, which is sometimes surrounded by an irregular scobicular circle. 

 On the lower surface the tubercles are larger than on the upper surface, where they 



