220 ECOLOGY AND LIFE HISTORY OF THE COMMON FROG 



Parker, E., 97 



Pearly granulations, 165 



Pearson, 84 



Penman, 139 



Pet-keepers, techniques, 202 



Phacus, 46 



Phenological map, 124 



interpretation, 123, 125, 126 



report, 122 

 Phenology, 177-81 

 Phosphate — 



graph of changes in, 77 



relation to spawning and choice of 

 pond, 77, 206 

 Poikilothermous effect, 1 17-18 

 Pollution, favourable to spawning, 159 

 Polygamy, functional, 160 

 Polyplacophora, 50 

 Polystoma integerrimum — 



change of larvae into neotenics, 59- 

 60, 64-5 



distribution in tadpoles, 62, 204-5 



effect of on size of tadpoles, 63, 205 



epizootics in tadpoles, 59-66 



epizootics, graphs of, 61-3 



population density as measure of 

 tadpole mortahty, 207-8 

 Pond-finding, 197-8 

 Ponds — 



spawn relation to chemistry, 75, 77- 

 8, 206-7 



spawn, relation to geology, 75-6, 

 205-6 



variation in use by frogs, 73-4, 83 

 Population — 



in the Alps, 88 



in Ireland, 88 

 Potassium, relation to choice of pond 



by frogs, 75, 206 

 Predators — 



of frogs, 65, 87-8 



of tadpoles, 65, 90 

 Pre-spawning period, 156 

 Psychology of tadpoles, 41-2, 154 



Rainfall — 



effect at the time of spawning, 127- 



31, 209 

 effect of on spawn-date, 133-8, 140, 

 143, 145-8 

 Rana — 

 agilis, 51 



Rana (contd.) — 



aurora, 14 



clamitans, 68, 85, ill 



esculenta, 5, 8, 54, 85, iii 



pipiens, 174 



pretiosa pretiosa, 66 



syluatica, 15, 42, 47, 173-4 



terrestris, 174 

 Razor, Occam's, 153, 175 

 Regression analysis of spawn dates, 142 

 Releasers, 171 



Respiration in tadpoles, 19-22, 53-6 

 Robins, mortahty compared with that 



of frogs, 85 

 Roesel von Rosenhof, 86, 159 

 Rovzewska, 98 

 Rowan, 121 



Royal Meteorological Society, 122, 177 

 Rugh, 13 



"Run-off", 145, 147-8 

 Russel, E. S., 154 

 Russel, W. M. S., 164, 171 



Scaphiopus holbrookii, 84-5 



Scenedesmus, 46 



Scillium, digestion in, 45 



Seurat, 9 



Sex recognition, 164-5, 172-5 



drawing showing male and female, 

 172 

 Significance, statistical and importance, 



distinction, 208 

 Smell of water due to algae, 72, 113, 



148-9 

 Smith, C. L., 96, 120 

 Smith, M. A., 68, 85, 87, 94 

 Snakes as predators, 87 

 Sokolov and ChvaUova, 45 

 Solomon, 91-2 

 Spallanzani, 9 

 Spawn dates — 



distribution in S.E. England, 147 

 map, 148 



negatively skewed, 147-8, 195 

 in British Isles, 123-6 

 map, 124 

 Spawn ponds — 

 events in, 160-3 

 relation of chemistry of water to, 75, 



77-8, 206-7 

 relation of geology to, 76, 205-6 



