204 INDEX 



XJngulata, 77 



Unicellular organisms, 14-15, 45 

 rhythmic motion of, 47, 134 

 shape of, 160 

 reproduction of, 161 



Urea, excretion of, 5, 8, 40, 100 



Vacuole, contractile, ll, 100 



of Infusoria, 133 



intervals of contraction, 133 

 Valves, in bats' wings, 138 

 Vascular bundles, 51, 55 (fig. 17) 

 Vegetable foods, 58 

 Vegetarians, 96 

 Vegetative cell, 174 

 Veins, of leaves, 54 

 Venus' Fly-trap, movement of, 119 

 Vertebrae (fish), concentric rings in, 



138 

 Vertebrata, food of, 66 



lungs of, 102 



not dominant species, 154 



reproduction of, 181 

 Vespa, 155 



Vesuvius, eruption of (1906), 105 

 Vibration of insects' wings, 103, 128 

 Vibrio, 27 



Viper, temperature of, 110 

 Vitamin A, B, C, 93, 94, 95 

 Vitamins, 57, 92 



essential to hfe, 93 

 Volvox aureus, 19 (fig 6) 



Washington elm, 34 

 Wasps, 62 



speciaHzed functions of, 154-5 



rhythmic activity of, 155, 157 



importance of queen, 158 

 Water, loss of, in transpiration, 

 54-5 



in food, 57 

 Water- worms, movement of, 126 

 Weevils, destruction by, 65 

 Westminster Hall, 64 

 Whales, Cetacea, whale-bone, food 

 of, 67, 76 



toothed, food of, 76 



spermaceti, 76 



kiUer, 76-7 



breathe in water, 111 

 Wire-worm, see Milhpede and Elaier 

 Wolf, Tasmanian, 74 

 Wombat, 74 

 Woodlouse, 47 



Xantharpyia collaris, 



84, 85 

 Xestobiiun tessellatum (death-watch 

 beetle), 64 



Yeast cells, 112 



division of, 161 



W\LLABY, 74 



Walrus, 83 

 Wapiti, 79 



ZoOIDS, 164 



asexual reproduction of, 167 

 Zoospores, 162 



Cambridge: printed by w. lewis, m.a., at the university press 



