REVIEWS AND EXCHANGES 
231 
tubers, bulbs, offsets and corms, frogs’ spawn, tadpoles, hen’s eggs and chicks, 
have their development traced week by week ; and buds, opening flowers, plant- 
defences, the movements of plants and plant-associations, earthworms, wood-lice, 
centipedes, silkworms, honey-bees, ants, snails and galls, form the subjects of 
further lessons. A single course from February to July is here outlined, but it 
I 
I 
i 
1 
I 
1 
The Under-side of a Snail. (From Eton Nat are- Study.) 
will be obvious to any teacher that this volume may be used for several years, or 
for classes of very different ages, by such slight modifications as will at once 
suggest themselves. Such subjects as plant-association, the flowerless plants, the 
variation in the beaks, feet and plumage of birds, the teeth of mammals, or the 
life -histories of insects, are capable of indefinite expansion. An appendix gives 
detailed information as to where all materials can be obtained, and the whole is 
illustrated with about 120 excellent drawings and photographs, of which we are 
