260 The Field Naturalist' s Quarterly August 



brates are described, and then the whole of the Invertebrates, begin- 

 ning with the Worms and ending with the Protozoa. Since the series 

 when complete will be a work of reference for the whole subject of 

 animal natural history, it is perhaps of comparatively little importance 

 in what order the various types of animals are considered. For 

 teaching purposes, however, we think it is of great importance that 

 the student should be led from the simple to the complex rather than 

 vice versa. 



The two half- volumes now completed review in brief the entire animal 

 kingdom as a necessary preliminary to the study of the food of animals, 

 the defences, and other aspects of life to be considered in the suc- 

 ceeding volumes. Already, however, many comparisons have been 

 drawn attention to in illustration of general principles, and particularly 

 has our author indicated the affinities between related groups. Thus 

 the principal characters which cause the birds and reptiles to be as- 

 sociated under the one term Sauropsida are contrasted with those which 

 place the amphibians and fishes together in the Ichthyopsida. This is 

 only one instance of the useful character of the work to non-specialist 

 readers. Of the illustrations by far the most useful to our mind are the 

 diagrammatic drawings, some of which are excellent. We wonder if Pro- 

 fessor Davis has verified for himself the statements on p. 194 explanatory 

 of the ease with which the tail of some lizards is broken, as in the slow- 

 worm, for instance. We have found the fracture in Anguis fragilis 

 and Lacerta viridis to be due to other causes than the supposed lack of 

 ossification in the centre of the vertebrae, but the explanation here given 

 is the orthodox one found in all text-books, and presumably copied from 

 one to the other. We must protest against the statement that the 

 " sand lizard {Lacerta agilis) is commonly found on sunny slopes in this 

 country" (p. 190), the distribution of this species being very limited 

 even in those counties south of the Thames, and distinctly limited 

 elsewhere. Neither do we quite agree with the general statement that 

 reptiles are in the main sluggish, though that, too, is the common 

 opinion. Our experience is that any particular movement in most 

 reptiles is carried out with as great rapidity, and sometimes with light- 

 ning speed, as is the case in similar movements of birds and mammals. 

 If anyone doubts this let him set free a sand lizard or a common 

 viviparous lizard on a lawn and try and catch it. It is excellent exercise, 

 but the result is disappointing. 



We have always maintained that photographs are better than coloured 

 plates for illustrating lizards, for the simple reason that the extent of 

 colour variation in them and also in snakes is so great that even an 

 accurate representation of one specimen is of no value as a standard 

 from which to judge the whole species. The coloured plate of lizards in 

 this volume confirms this view. 



The best part of this half-volume is that on the Insects. Here the 

 diagrams and other illustrations are good, the classification simply 

 described, and the life-histories useful. 



We look forward with interest to the succeeding volumes, which, being 



