Plant and anijoal protection regulation .« 193 



Plant control, potash in 160 



Plant eaters 11 



Plant growth, removal 152, 158 



Plant world ^ 



Plants, emergent 41 



Plants, floating 42 



Plants , oxygen production by 42 



Plants, underwater 42 



Plow, motor tractor 159*, 160» 



Plowing 158, 159*, 160* 



Pocks disease 199 



Polar diver 193 



Polecat, litis 193 



Pole-grate structure 177, 179, 178», 179» 



Pole scraper net, Friedrichshagen model 41 



Police fishes 93 



Pollution and small fauna 35 



Polyarthra 32 



Polycistis 45 



Polygonum 43 



Polypedilum 33 



Polyphemus 32 



Pond area, least 78, 125 



Pond bottom 58, 61, 64 



Pond bottOTi, cultivation of the 85, 158, 162 



Pond, brown-water 30 



Pond, conception of the 61 



Pond construction 61, 69 



Pond construction, costs 69 



Pond, Dubisch 80, 82* 



Pond, dystrophic 31 



Pond fertilization experiments 167 



Pond fertilization, nitrogen free 171 



Pond fish-out 84* 



Pond fishery, plan of a 78« 



Pond fishes, natural feeding in nutrition of 10 



Pond fishes, nutrition by artificial feeding 15 



Pond fishes, nutrition of the 10 



Pond industries German, natural yield of 127 



Pond industry, size classes of the 70 



Pond, living conditions in the 27 



Pond plankton 32 



Pond, pre-extension (nursery) 84 



Pond, production conditions in the »• 27 



Pond, regions in the • 28 



Pond sluice, see also Sluice 64, 66*, 67, 68 



Pond swimmers (Colymbetes ) ••• 34 



Pond types °1 



Ponds , age and yield of 31, 158 



Ponds , autotrophic 31 



Ponds for brood extension 85, 86, 159 



Ponds for trout mast 126, 149 



Ponds , heterotrophic 31 



Ponds , lime-poor 1"5 



Ponds, masting 126, 149 



Ponds, maturing 88, 88», 124, 126» 



Ponds , naturally dammed 191 



Ponds , spawning • ^0 



Ponds , trout-brood 1^3* 



Ponds , water supply of °2 



Ponds, winter (hibernation) 182, 182* 



250 



