76 TEE ZOOLOGIST. 



NOTICES OF NEW BOOKS. 



The Tanganyika Problem; an Account of the Researches under- 

 taken concerning the Existence of Marine Animals in Central 

 Africa. By J. E. S. Moore, F.R.G.S. Hurst & Blackett. 



It is well within the memory of many, when Burton first dis- 

 covered Lake Tanganyika. Africa was then a dark continent, to 

 be only traversed by the adventurous leader of a big expedition ; 

 to-day it is an ordinary goal for a sportsman, and will soon be 

 tramped by the Cook's tourist. The discovery of the lake was 

 the event of a geographical season ; we are now studying the 

 origin of its fauna, which is the " Tanganyika problem " which 

 this volume has brought into the domain of real zoological 

 philosophy. The interest in the question has long been accumu- 

 lating from the time when Speke brought home a few shells he 

 had picked up on its shores, and which were recognized as 

 curiously marine. Then Jelly-fishes were discovered in the lake 

 by Dr. Bohm, and a British expedition — purely biological — was 

 despatched in 1896 under the direction of the author of this 

 work. The most definite result of that expedition appeared to 

 be that " the sea had at some former time been connected with 

 the lake, but when or how remained a mystery." Prof. Ray 

 Lankester, who had organized the first expedition, now initiated 

 a second one, and Mr. Moore again started in 1899 for the 

 lake, whose marine molluscs compare, every one, with indi- 

 vidual prototypes in the remains of the old Jurassic Seas. 



The problem was complicated by one of those speculative 

 assumptions which so often crystallize as dogmas in scientific 

 generalizations. Sir Roderick Murchison, from an examination 

 of then available geological and other facts, had concluded that 

 the interior of Africa had never been beneath the sea, and con- 

 sidered his view was confirmed by the absence south of the 

 equator " of all those volcanic activities which we are accustomed 

 to associate with oscillations of terra firma." Consequently, to 



