_Pomatias_, 49, 321-322 _Pontoporeia affinis_, 179 Porto Santo, molluscan fauna of, 25 Pouched Marmot, 41 Praeger, R. L., 298 Praying insect, 269 _Proboscidea_, origin of, 252 _Psammodromus algirus_, 295 _hispanicus_, 295 Ptarmigan, 91, 142 _Pupa_, antiquity of, 50 _Pupa_, 297-298 _anglica_, 298 _granum_, 297 _ringens_, 102 _Pyrrhocorax alpinus_, 317 _Pyrrhula_, 191, 255 _europæa_, 191, 256 _major_, 191, 256 Rabbit, introduction of, 27, 31, 291 _Rana temporaria_, 194, 320 Range, extension of, 38 _Rangifer tarandus_, 133, 150-158 Reade, Mellard, 127-129 Red Crag, Arctic molluscs in, 235-236 Red Deer, 246-250 Red Grouse, 91, 142 Red-legged Partridge, 29 _Regulus ignicapillus_, 257 _maderensis_, 257 _teneriffæ_, 257 Reid, Clement, 76, 163 Reindeer, range and varieties of, 91, 133, 149-158 Relict lakes, 176-179, 223 Reptiles, dispersal of, 21 Reptiles of Europe, 192-193 _Rhax_, 270 Rhinoceros, distribution of, 214-216 _Rhododendron ponticum_, 271 _Rhopalomesites Tardyi_, 302 Rock Sparrow, 318 Route of migration of Siberian mammals, 210 _Rupicapra tragus_, 312 Russia, marine transgression in, 172 submergence of North, 155 Rütimeyer, L., 43, 57, 281 _Ryothemis_, 269 Saiga Antelope, 39, 204 _Saiga tartarica_, 39, 204 _Salamandra atra_, 319 _caucasica_, 319 _maculosa_, 319 _Salmonidæ_, origin of, 92, 143 Sandgrouse, migration of Pallas's, 41, 205 Sars, O., 177, 223-224 Saunders, H., 256 Seal, Arctic, 174 Sea-urchin, 125 Sedgwick, A., 86 Scandinavia, absence of Oriental and Siberian mammals from, 176, 206 during Glacial period, 176 Scandinavian boulders, origin of, 172-173 butterflies in America, 167 flora, antiquity of, 162, 185 glaciers, 172 Scandinavian lepidopterous fauna, 55 Schulz, A., 52, 155 Sclater, P. L., 95 Scotch Argus, 325 Scotch and Irish Hare, 136 Siberia, climate of, during Glacial period, 217 Siberian birds in British Islands, 191-192 mammals absent from Scandinavia, 176, 206 mammals absent from Southern Europe, 206 mammals in Great Britain, 95-96, 190, 202-204 migration, date of, 208 steppe-fauna, 39 Sicily, Pliocene deposits in, 277 _Silurus glanis_, 29 Simpson, C. T., 21 Simroth, H., 48, 299 Sjögren, H., 226 Slugs, dispersal of, 16-17 Snails, dispersal of, 17 Snow-Bunting, range of, 91, 140 Snow-Finch, 318 Sollas, W., 177 _Somateria mollissima_, 141 _Sorex_, 202, 314-315 _alpinus_, 314-315 _araneus_, 315 _minutus_, 315 Southern mammals in Arctic Siberia, 213-216 Sparrow, introduction of, 28 _Spermophilus_, 41 Speyer, A. and A., 55, 200 Spiders, Lusitanian, 301 Sponges, American, in Ireland, 166 St. Erth fauna, 174 Steinbock, 312 Steppe-fauna, Siberian, 39 Sterlet, introduction of, 29 Stick-insect, 269