i 7 2 SCIENCE PROGRESS 



The earlier part of the volume is devoted to the treatment of seed dispersal in 

 the West Indies, and, with this object in view, the drift of the Turks Islands is 

 considered in detail. The author maintains that here the West Indian drift is ex- 

 hibited in an early stage of its transit of the Atlantic, towards the coast of Europe. 

 The wisdom of this choice is shown by the fact that one-third of the fruits and 

 seeds found in the drift of Turks Islands has, at one time or another, been stranded 

 on European coasts. Something of romance attaches to the history of the tropical 

 drift, comprising some dozen species which have made this journey of nearly 

 4,000 miles, and it is scarcely surprising that superstitions and traditions have 

 grown up around the Molucca beans and Mary's beans of Northern folklore. The 

 most frequently occurring seeds are those of Entada scandens and other members 

 of the Leguminosae. 



An excellent summary of the records of bottle drift, etc., forms the basis for 

 a consideration of the ocean tracks and the rapidity of travel. It would appear 

 that not only is the drift, of the West Atlantic seaboard, carried by the Gulf Stream 

 in about fourteen months to all parts from Norway to Morocco, but the return 

 journey is accomplished in about sixteen months by the agency of the North 

 Equatorial Current. 



Similarly the South Atlantic has its own circulatory system of currents, and 

 it is estimated that the passage from the Gulf of Guinea to Brazil would generally 

 occupy not more than twelve weeks — a period sufficiently short to be effective 

 in the dispersal of germinable seeds. In illustration of this, fifty-three character- 

 istic littoral, estuarine, and riverside plants of the West Indies are enumerated, 

 of which thirty-two flourish on the West Coast of Africa. All of these, except four, 

 have seeds or fruits capable of retaining their vitality in sea water for a sufficient 

 length of time to have been transported by the main Equatorial Current. 



An interesting account is given of the Geology and Flora of Turks Islands, and 

 Mr. Guppy takes the opportunity of supporting the view that the ultimate basis of 

 Evolution is geographical environment. He regards the cosmopolitan families 

 and genera as the more primitive, characterised by an absence of specialisation 

 that enables them to occupy a wide range. Willis's work, however, on the Ceylon 

 Flora led him to conclude that the species with a restricted range were those of 

 recent origin. The truth may well lie between these two extremes, but in any 

 event the Differentiation Theory here advocated does not appear to us so incom- 

 patible with modern evolutionary views as the author maintains. 



In the final chapters a description of the Vegetation of the Azores is given, and 

 stress is laid on the small number of species that are truly native. One is par- 

 ticularly struck by the close similarity of the moorland flora and that of the upland 

 lakes to the corresponding plant associations in this country. 



If one has any criticism to offer it is that the author's thesis is sometimes 

 obscured by detail which, though intrinsically valuable, distracts from the con- 

 tinuity of the major theme. 



E. J. Salisbury. 



ZOOLOGY 



An Introduction to a Biology and Other Papers. By A. D. Darbishire. 

 [Pp. xviii + 291.] (London: Cassell & Co., Ltd., 1917. Price 7s. 6d. net.) 

 IN A. D. Darbishire the war claims another victim from the rank of English 

 biologists. Although not killed in the field he died in camp a private in the 

 Argyll and Sutherland Highlanders three days before he was gazetted to the 

 Royal Garrison Artillery. He had already made a name for himself by his 

 contributions to current biological theory and for his frank criticism of various 



