724 SCIENCE PROGRESS 



passes on to a consideration of the cell and cell theory ; although both are 

 brief, they are well written. Nine chapters are devoted to types and a general 

 consideration of the phylum to which each belongs. The mode of treatment is 

 excellent ; throughout structure and function, ecology and behaviour are co- 

 ordinated, whilst short accounts of the embryology and bionomics add greatly 

 to the interest. 



There is much to be said in favour of even the beginner extending his know- 

 ledge beyond the actual "type" and the method advocated by Dr. Hegner 

 strongly commends itself to us. The various " types " are treated as living 

 organisms whose activities are of fundamental importance — hence the morphology, 

 although fully dealt with, is not specially emphasised. 



There is an interesting chapter dealing with historical zoology and a final one 

 treating of general considerations of zoological facts and theories. This latter is 

 perhaps the weakest ; but we fully realise the difficulties of doing justice to the 

 subject in thirty pages. We welcome the chapter on historical zoology, which 

 might have contained more information even in fewer words. 



On the whole, Dr. Hegner's work deserves every praise and zoologists 

 generally will welcome so interesting and lucid an exposition in remarkably 

 small space. 



Walter E. Collinge. 



The Geology of Water Supply. By Horace B. Woodward, F.R.S., F.G.S. 

 [Pp. xii -1- 339.] (London : Edward Arnold, 1910. Price 7s. 6d. net.) 



In a long life spent in the service of the Geological Survey, the author has had 

 exceptional opportunities of obtaining information on the difficult subject of the 

 distribution and movements of underground water, knowledge of importance for 

 the health of the community and the prosperity of its industries. That it is 

 still very imperfectly understood, the unexpected irruption of great volumes of 

 water into the sinkings for coal in the south-east of England is sufficient proof. 

 In the present volume we have, so to speak, the contents of the authors capacious 

 note-book placed unreservedly at our disposal, so that it constitutes a mine of 

 wealth for those who are seeking for information. One could wish he could have 

 seen his way to discard some of the technical terms at present in general use, 

 which, embodying as they do the incorrect ideas of the past, only serve to mis- 

 lead the student. Why, for instance, should we refer to the underground surface 

 of saturation as a ' water table,' when it is well known that it is rarely truly 

 horizontal ; or as a ' plane of saturation,' when it is usually distinctly curved ? 

 If a short expression is desired, water surface would answer every requirement. 



Of especial value is the systematic account of the water-bearing characters of 

 the different formations in this country, which is as detailed and reliable as we 

 expect to be the case when we know it is from the pen of the author of the " Geology 

 of England and Wales." 



In his preface the author pays a well-deserved tribute to Mr. Whitaker, to whom 

 we owe so much in this country for our knowledge of the relations of underground 

 water to the geological structure of the rocks. 



John W. Evans. 



Phases of Evolution and Heredity. By Berry Hart. [Pp. xii + 259.] 

 (London : Rebman Ltd., 1910. Price ^s. net.) 



To the person who requires a knowledge of these two all-important scientific 

 problems without wishing to enter into the elaborate and complicated details to 



