28 



FAUNA OF BALUCHISTAN. 



H. delettrei 



H. striato-radiatus 



H. af 



B. pyrenaicus 



= 0-92. 

 = 091. 

 = 0-90. 



• • • • = 0*83 ^" *o8» 



We see that in E. leymeriei, H6b., length and breadth are nearly equal, while 

 there exists a considerable difference between the two measurements in H. pyren- 

 aicus ; the shape of the circumference of the different species varies therefore con- 

 siderably, while, so far as my observations go, it is not even constant in individual s 

 of the same species. 



As regards the ratio h-i-L we have the following table : — 



B, afrieanus 



E. striato-radiatus 



H. delettrei 



E. pyrenaicus 



B. leymeriei . 



B, cornpresBus 



•90, 

 •74. 

 ■66. 

 •64. 

 •64. 

 •59. 



> We see, therefore, that the height of the various species fluctuates between 

 considerable limits, so that the amplitude may vary much, though the circumference 

 remains the same ; for the latter the amplitude is 'lO— -15, for the first 'SI ; in 

 other words, there exist high conical forms in which the height is nearly equal to the 

 length, and low depressed forms where the height is only slightly in excess of half 

 the length. On the plate opposite I have depicted the outlines of the various known 

 species of Hemipneustes which will convey a much better idea of ' the characteristic 

 shape of each species than words can do. 



If we now consider the geological position of the above six species, it will be 

 seen that they all occur in the upper beds of the cretaceous system, the 6tage 

 Danien of the French. This is of great importance as regards the development of 

 the cretaceous system in Baluchistan, because we may justly infer that the same 

 species which elsewhere characterise the etage Danien will be found in Baluchistan 

 at the same horizon. 



As regards the geographical distribution of the genus Eemipneustes we have 

 here one of the strange and well nigh inexplicable instances of the distribution of 

 animal life. According to various authors the hitherto known five species have 

 been distributed as follows : — 



1. Hemipneustes striato-radiatus, Lesk., Maestricht, Dordogne(?) 



2. „ pyrenaicus, Heb. . 



3. „ leymeriei, Heb. 



4. ,, a/tieanus, Cott, . 



5. „ delettrei, Cott. . . 



irrenees. 



' j- Algiers (Prov. Conetantine). 



And now we have in Baluchistdn the following species :— 



Eemipneustes pyrenaicus, Heb. 

 „ leymeriei, Heb. 



„ eompressus, spec. nov. 



