NA TURE 



397 



THURSDAY, JULY 13, 1916. 



BRITISH MARINE ANNELIDS. 



A Monograph of the British Marine Annelids. 

 Vol. iii. , part i. Text. Polychaeta : Opheliidae 

 to Ammocharidae. By Prof. W. C. Mcintosh. 

 Pp. viii + 368. Also vol. iii., part ii. Plates 

 Ixxxviii-cxi. (London: Dulau and Co., Ltd., 

 1915.) Price 25s. net each volume. 



'T'HE first part of the first volume of this mono- 

 -^ graph of British Annelids dealt with the 

 Nemertine worms. The second part of the 

 first volume, the two parts of the second volume, 

 and now the third volume are devoted to the 

 Chaetopoda, and still the great work is incomplete. 

 At least one more volume will be required before 

 the order Polychaeta is finished. 



The third volume includes those families that 

 were grouped together by Benham in the sub- 

 orders Spioniformia, Capitelliformia, and Scoleci- 

 formia, together w ith the family Cirratulidae of the 

 sub-order Terebelliformia. 



The author has not adopted in his monograph 

 any system of grouping the families into sub- 

 orders such as that suggested by Benham, and it 

 is rather awkw^ard for the zoologist who is not a 

 specialist in the Chaetopoda and does not know the 

 sequence of families which Prof. Mcintosh em- 

 ploys that he has no guide to the position in the 

 three volumes of any family he w^ishes to study, 

 nor a list of those that have still to bfi described. 



No doubt the author will prepare a tabular state- 

 ment of the classification of the order for the last 

 volume, but it would have been a great conveni- 

 ence if he had included in each part a list of all the 

 families arranged in the order of their treatment. 



We make this comment in the first place because 

 the monograph is on a much higher plane than 

 many of the systematic treatises on zoology with 

 which we are acquainted, and it is important in 

 the interests of science that everything should be 

 done to facilitate its use. 



The present volume includes many of the most 

 important of the marine worms, such as the 

 Arenicola (or lug-w^orm of the fisherman), the 

 phosphorescent Chaetopterus, the Spionidae, the 

 rock-boring Polydora, and the morphologically 

 Interesting forms Magelona and Capitella. In 

 studying the chapters on these important worms 

 the reader must be impressed not only by the vast 

 amount of labour and learning bestowed upon their 

 systematic treatment, but also by the author's 

 generous appreciation of the anatomical, physio- 

 logical, and embryological knowledge concerning 

 them that has accumulated during recent years. 

 It is clearly show^n on every page that infinite pains 

 have been taken with the tedious but necessary 

 and valuable work of completing- the lists of 

 synonyms and references to species; but intimate 

 knowledge and life-longf research have also been 

 employed in summarising what is known of the 

 morpholoev of the species described. The mono- 

 graph stands, therefore, as an important contrlbu- 

 NO. 2437, VOL. 97] 



tion to our general knowledge of the order as a 

 whole, as well as a descriptive catalogue of the 

 species that inhabit the British sea area. It is a 

 standard work of the highest importance, and we 

 may be proud of it as a product of British science. 

 It is unfortunate that our final judgment of the 

 illustrations must be suspended. Six of the twenty- 

 four plates that illustrate part ii. of this 

 volume were to have been issued in colours, but 

 in consequence of the war they have not yet been 

 delivered, and to prevent further delay in publica- 

 tion uncoloured copies have been substituted for 

 them. This is undoubtedly a serious misfortune, 

 and we may cordially extend to Prof. Mcintosh 

 our good wishes that in the coming times of peace 

 the coloured plates may be recovered. In the 

 meantime, however, we may say that, apart from 

 this drawback, the illustrations are at least equal 

 to the very high standard attained by those of 

 the earlier volumes, and add immensely to the 

 value of the monograph. S. J. H. . 



COLLOIDAL SOLUTIONS. 



The Physical Properties of CoUoidal Solutions. 

 By Prof. E. F. Burton. Pp. vii + 200. (London : 

 Longmans, Green, and Co., 1916.) Price 65. 

 net. 



THIS work forms one of the series of mono- 

 graphs on physics edited by Sir J. J. Thomson, 

 and it is perhaps natural that the author should 

 have practically confined himself to discussing that 

 class of colloidal solutions which has so far proved 

 amenable to quantitative and mathematical in- 

 vestigation — the class known as suspensoids. 

 The treatment of the emulsoids is very brief and 

 inadequate, an omission all the more striking as 

 the author several times insists on the importance 

 of colloidal physics to the arts and to biology and 

 physiolc^y, the former of \vhich are largely, and 

 the latter exclusively, concerned with emulsoids. 



Within these limits, however, the treatment is 

 full and very clear. The chapter on preparation 

 and classification gives all that is necessary in a 

 small compass. In that on the ultramicroscope 

 the author has gone a good deal further than is 

 usual, and perhaps necessary, by including a brief 

 account of the principval theories of image forma- 

 tion and resolving power. The chapters dealing 

 with the theory of the Brownian movement — to 

 the physicist the crowning achievement of col- 

 loidal sciences-are admirable and give the best 

 historical account, as well as the clearest pre- 

 sentation, of the mathematical work of Einstein, 

 V. Smoluchowski, Langevin, and Perrin at pre- 

 sent available in any text-book. The optical 

 properties are also treated with unusual fulness, 

 while the electrical ones receive ample, but not 

 excessive, attention. The frank confession — 

 which probably only one of the best-known 

 workers in this much-tilled field can afford to 

 make — that the stability of sols is still a puzzle 

 is to be welcomed. Adsorption is only touched 

 upon as bearing upon electrolyte coagfulation, 

 and the statement that the adsorption isotherm 



