586 



INDEX 



Pirula, 188 



Pisidium, dispersal, 62, 83, 123, 130, 290, 

 309, 312, 316, 331, 332, 333, 363, 

 364, 367, 368, 374 

 Pissodes, 544 

 Placostomus, 314, 315 

 Plagiostomum girardi, 190 

 P. lemani, 333, 364 

 Planaria, 330, 367, 373, 532 

 P. alpina, 30, 93, 131, 307, 308, 309, 312, 



331, 333, 349, 364, 365, 373, 529 

 P. anopthalma, 529 

 P. gonocephala, 93, 307, 308, 309 



a eurythermal form, 14 

 P. montenegrimi, 527, 529, 533 

 P. velata, 352 

 P. vitta, 373, 533 

 Planarians in Lake Baikal, 345 

 Planes minutus, 245, 246 

 Planktomya, 224, 225, 238 

 Plankton, 233 



African lakes, 360 



amount in lakes, 336 



composition, 240 



destruction by storms, 242 



feeders, 237 



fresh-water, annual variation, 337 



of ponds, 349 



of rivers, 302 



relation to current, 303 



seasonal variation, 339 



stratification in lakes, 337 



transported by the Gulf Stream, 59 

 Plarwrbis, 83, 85, 123, 347, 354, 363. 367, 



550 

 P. albus, 333 

 P. rotundatus, 130 

 Platanista, 311 

 Platycleis, 66 



Platymaia wyviUe-thomsoni, 353 

 Platytelphusa, 347 

 Plautus, 483 

 Plethodon, 437 

 Pleurobrachia pileus, 278 

 Pleurodiran turtles, 109 

 Pleurodonta gigantea, 400 

 Pleuronectes flesus, 39, 81 

 P. microcephalus, 195 

 P. platessa, 167, 195, 310 



variation in egg size, 40 



Pleurotoma, 152 



Pleurotomaria, 53, 126 



Ploesoma hudsoni, 339 



Plumatella, 312 



P. princeps var. spongiosa, 310 



P. repens, 346 



Plusia gamma, 67 



P. moneta, 121 



Pneumatophores, 226 



Pocillopora, 60 



P. /croosa, 218 



Pocock, 72 54 , 97 s2 



Podisma frigida, 498 



Podoces, 449 



Podow, 241, 283 



Pogonomyrmex, 461 



Pogonomys, 425 



Poikilothermal animals, 394 



Polar bear, swimming, 65 



Polar fresh-water communities, 361 



Polar lakes, 325 



Polar marine communities, 274 



Polar regions, 505 



Polar waters, poverty of fauna, 362 



Polinski, 96 55 



Polistes, 401 



Pollicipes, 53 



Pollution of Illinois River, 550 



of the Thames, 18 

 Polyarthra platyptera, 339 

 Polybius, 232 

 Polycelis, 330 



P. cornuta, 93, 131, 307, 308, 309 

 P. nigra, 331 



Polychaete worms in Lake Baikal, 346 

 Polygordius, 184 

 Polynoe, 256 

 Polyommatus, 508 

 P. phlaeas, 394 

 P. phlaeas eleus, 394 

 Polypedates, 432 

 P. leucomystax, 548 

 Polyphemus pediculus, 349 

 Pomatias rnaculatum, 68 

 Ponds, fauna of, 348 

 Pontophilus, 264 

 Pontoporeia affinis, 38, 140, 348 

 Popella guerni, 304 



Popillia japonica, rate of development, 

 15 





