ago JOURNAL OF CONCHOLOGY, VOL. l6, NO. 9, JUNE, I922. 



a mountain which lies quite beyond the eastern limits of the Congo 

 drainage basin, and although this "truly Epiphallogonous " species is 

 viewed by Prof. Pilsbry as probably a degenerate Euadeniate, it may 

 easily belong to a laggard group of true Epiphallogona which has 

 become isolated from the main body of their congeners, and compelled 

 to ascend the mountain heights to escape the competition and en- 

 croachments of the later evolved and advancing Euadeniates. For 

 although the learned author has laid it down as a law " that the 

 active centres [of evolutionary activity] for land moUusks are invari- 

 ably in or about mountain regions/' yet this declaration is quite 

 opposed to the teachings of Darwin and the views of other students 

 of geographical distribution. 



Mountain regions or lofty summits frequently harbour a rich and 

 distinct fauna and flora, l)ut these are usually due to the congregation 

 there of the more primitive and weaker species which previously 

 inhabited the surrounding country, and any change they may undergo 

 will probably be in the way of structural adaptation to the special 

 environmental conditions they may be compelled to endure, and are 

 therefore more probal)ly a mark of degeneration, rather than of 

 progress, or as Darwin has so poetically expressed it "as the tide 

 leaves its drift in horizontal lines, rising higher on the shore, where 

 the tide rises highest, so have the living waters left their living drift 



on our mountain summits The various species thus 



stranded may be compared with the savage races of men, driven up 

 and surviving in the mountain fastnesses of almost every land, which 

 serves as a record, full of interest to us^ of the former inhabitants of 

 the surrounding lowlands." 



This remarkable book is, however, truly a veritable treasure-house 

 of information on every aspect of the Central African land mollusca 

 and it is the first book on that region which authoritatively and 

 almost exhaustively treats upon those structural characters which are 

 the most reliable basis of a truthful and natural classification. 



With this fine volume as a forerunner we look forward with eager 

 anticipation to the second volume, in which the freshwater species 

 will be treated of, and which in addition will also be enriched by the 

 final results of Prof. Pilsbry's philosophical study of the characteristics 

 and relationships of tropical African mollusca generally. 



NORTH GRANGE, HORSFORTH, 

 April, ig22. 



