2l8 



NATURE 



[May II, 1916 



THE FRESH-WATER FISHES OF AFRICA. 

 Catalogue of the Fresh-water Fishes .of Africa in 



the British Museum {Natural History). Vol. iv. 



By Dr. G. A. Boulenger. Pp. xxvii + 392. 



(London : British Museum (Natural History), 



and Longmans, Green and Co., 1916.) Price 



30s. 



THE British Museum has recently published 

 the fourth volume of Mr. G. A. Boulenger's 

 "Catalogue of the Fresh-water Fishes of Africa." 

 Thus is brought to a conclusion — at any rate, for 

 some years to come — a work of very great value. 

 Mr. Boulenger's research in*^o the ichthyology of 

 the African rivers and lakes has gone far beyond 

 a mere catalogue of species. It began to attract 

 attention nearly twelve years ago by the light that 

 it threw on the past geological history of Africa, 

 the former superficies of this continent at different 

 times in regard to rising and falling levels of land, 

 the connections of the continent with outlying 

 islands, the desiccation or the flooding of great 

 areas of land in the interior, the increase or the 

 restriction of river basins and of lake limits. 

 Briefly summarised, it went to show that the Nile 

 system in past times has been in direct communi- 

 cation with the now isolated Lake Rudolf, and 

 has come very near to the Chad Basin, which 

 again has communicated intermittently with the 

 Niger, while the Niger or its upper portion may 

 at one time have had an outlet into the Atlantic 

 in common with the Senegal, and have been 

 separable by only a few miles of land from the 

 upper waters of the Gambia, the Volta, and of 

 all those streams that flow from north to south 

 through the forests of Guinea and the Gold Coast 

 into the great African Bight. On the other hand, 

 it showed a comparative poverty and isolation in 

 fish fauna of the Zambezi Basin and South 

 Africa ; and it illustrated, above all, the specialised 

 character and wealth in fish-fauna of the Congo 

 Basin. This region (with which Tanganyika was 

 not always connected) must have approached very 

 closely to the upper waters of the Gaboon and 

 Cameroons rivers to account for the near relation- 

 ship between their fish-fauna and that of the Congo 

 Basin. 



So far back as 1870, Dr. Giinther, of the 

 British Museum, could only catalogue about 255 

 species of African fresh-water fish. Mr. Bou- 

 lenger raised this number in 1906 to 974; but he 

 is enabled in the volume now under review to put 

 the total of species at 1425. 



In this amazingly complete survey of African 

 fishes he has been helped by many enthusiastic 

 collectors and students, and directly or indirectly 

 by the Belgian, French, and Luxembourg Govern- 

 ments, as well as by those of Egypt and the Union 

 of South Africa. Volume iv. of this magistral 

 work deals with the fresh-water Gobies, the Ana- 

 bantids or "climbing perch," the Mugilids or 

 Mullets, the Blennies, the Mastacembelids (anguine 

 in form, and so often taken by negroes to be 

 water snakes because many of them are hand- 

 somely marked with viperine patterns), and the 

 Tetrodonts. In addition, there is matter supple- 

 NO. 2428, VOL. 97] 



mentary to the other volumes, which gives us 

 further information in regard to the presence of 

 " saw fish " sharks (Pristis) in the rivers of 

 Portuguese Guinea ; additional knowledge of 

 the Polypterids of Portuguese Guinea and 

 Liberia, and of that very interesting aberrant 

 type, the Calamichthys of Calabar; of the Mor- 

 myrids of the Juba River (Somaliland) and of 

 Portuguese Guinea, Northern Zambezia, the 

 Upper Wele, Lake Bangweulu, and the Lower 

 Niger; of the fresh-water herrings of Angola, 

 the Characinids of western Congoland and Portu- . 

 guese Guinea, Cyprinids from all parts of Africa, 

 including the far south, and Silurids of an equally 

 wide scope- (It is interesting to note, by the 

 way, that there is a species of fish — Salarias, a 

 Blenny — shared between Madagascar and 

 Reunion Island.) 



A tribute is justly paid by Mr. Boulenger to 

 the magnificent collecting work accomplished by 

 the late Dr. W. J. Ansorge, who, after exploring 

 Uganda and other parts of Africa in the medical 

 service of the British Government, devoted him- 

 self, on his retirement, to a systematic examina- 

 tion of the fish (and other) fauna of Portuguese 

 West Africa, especially Angola and the little- 

 known Portuguese Guinea. It is to be hoped that 

 men like these, who have died in the prosecution 

 of really noteworthy scientific research, might be 

 commemorated by tablets let into the walls of the 

 British Museum of Natural History. 



H. H. Johnston. 



THEORETICAL AND PRACTICAL 

 CHEMISTRY. 

 (i) The Theory of Valency. By Dr. J. Newton 

 Friend. Second edition. Pp. xiv+192. (Lon- 

 don: Longmans, Green and Co., 1915.) Price 

 55. net. 



(2) Qualitative and Volumetric Analysis. By 

 W. M. Hooton. Pp. 86. (London : Edward 

 Arnold, 1915.) Price 35. net. 



(3) Laboratory Manual arranged to accompany 

 "A Course in General Chemistry." By Profs. 

 W. McPherson and W. E. Henderson. Pp. v+ . 

 141. (Boston and London : Ginn and Co., i 

 1915.) Price 35. " 



(4) The Rugby Course of Elementary Chemistry. 

 By H. P. Highton. Pp. 79. (London : Edward 

 Arnold, 191 5.) Price 25. 6d. 



(i) T^HE perusal of a treatise on valency 

 -»• leaves an impression of incompleteness 

 and uncertainty, of a mass of theories no single 

 one of which can claim to correlate and interpret 

 more than a portion of the relevant facts. This 

 aspect of the matter, to which reference was made 

 in the review of the first edition of Dr. Friend's 

 excellent volume (Nature, 1909, Ixxx., p. 395), 

 has been accentuated by recent work on radio- 

 activity, and the modified views with regard to 

 chemical combination and valency to which this 

 work has led. The author, although fully aware 

 of the extent to which earlier conceptions are 

 undergoing change, points out that nothing like 

 finality has been reached. He therefore does not 



