OF THE HALOLIMNIC FAUNA OF LAKE TANGANYIKA. 351 



portion of a former ocean-fauna, when we recollect what is well 

 known of the relations and the affinities of the faunas of the Permian 

 and Muschelkalk inland seas or lakes. 



"The case of the distribution of the modern sturgeon is very 

 suggestive. 



" Yours very truly, 

 " A. Irving, D.Sc' 



P.S. — The suggestions and enquiries of Dr. Irving, which are very 

 relevant to the problem, are to a greater or less degree dealt with 

 by the author of the paper, but are none the less valuable as coming 

 from an independent source. — Ed. 



