326 JOURNAL OF CONCHOLOGY. 



The Dispersal of Shells: An Enquiry into the Means 

 of Dispersal Possessed by Freshwater and Land Mollusca, 

 by Harry Wallis Kew, F.L.S., with a preface by Alfred 

 Russel Wallace. 



Kegari Paul, Trench, Trubner & Co. Ltd., 1893. 5/-. 8vo, 

 pp. 291. 



This work, which forms the 75th volume of the well-known 

 " Liternational Scientific Series," is a welcome and valuable 

 addition to the literature of a somewhat neglected subject, 

 though replete with interest not only to the student of geo- 

 graphical distribution but to conchologists and scientists 

 generally. 



The author agrees with the opinion of Darwin, Wallace, 

 and others that the great and repeated changes in the con- 

 figuration of the earth's surface, solely relied upon by some 

 authors to account for the distribution of organic life, are not 

 always necessary for its explanation, and that in the case of the 

 Mollusca the involuntary dispersal by the aid of man, other 

 organisms, or by the operation of natural forces is, in many 

 cases sufficient to account for their dissemination. 



Mr. Kew treats the subject under nine heads, dealing first 

 with what he has termed anomalies in local distribution, in- 

 stancing the cases of isolated or comparatively newly made 

 bodies of water, which have become possessed in a short time 

 of a special molluscan fauna — the two representative forms 

 that usually seem to be among the first to appear are L. peregra 

 and S. corneiim. The fauna of some of the isolated ponds 

 mentioned are of great interest, sometimes containing species 

 not known to be living elsewhere in the district, and whose 

 presence seem only to be accounted for by the action of one or 

 other of the dispersive means suggested by the author. 



The second^ third, fourth, sixth, and seventh chapters are of 

 special interest, and deal in detail with many of the means of 

 dispersal, and citing numerous well authenticated instances of 



J.C., vii. , Jan. 1894. 



