_Cricetus frumentarius_, 190 _vulgaris_, 204 Crimea formerly an island, 35 Crimean fauna, 57 Croll, J., 66 _Crocidura_, 253 _etrusca_, 253, 279 _Cuniculus torquatus_, 138 Current, Arctic, 172-173 _Cyanopolius Cooki_, 293 _cyanus_, 293 _Cyclostoma elegans_, 16 _Danais chrysippus_, 267 Dartford Warbler, 288 Darwin, C., 13-15, 17-19, 25, 32-33, 339 _Daudebardia_, 323 _Daulias luscinea_, 192 Dawkins, Boyd, 53, 62-63, 72-73, 107, 112-113, 120, 208, 222-223, 282 Day, F., 29 Depéret, C., 44, 276 Dippers, origin of, 255 _Discoglossus pictus_, 279, 295-296 Dispersal of Amphibia, 59 of beetles (_apterous_), 59 of British butterflies, 113 of earthworms, 58 of planarian worms, 59 of spiders, 59 of wood-lice, 59 Distribution, centres of, 12, 43, 47 discontinuous, 114 Dormouse, 316 absent from Ireland, 121 _Drapetisca socialis_, 94 _Dreyssensia polymorpha_, 26, 230-231 Drift, a marine deposit, 129 Drude, O., 52, 77 _Dryas octopetala_, 79, 238 Dual origin, possibility of, 38 Dyer, Th., 79 Earth-worms, distribution of, 19, 23, 58 Edelweiss, 266, 342 Egean Continent, subsidence of, 272-273 Eider-duck, range of, 141 _Elephantidæ_, origin of, 202, 252-253 _Elephas primigenius_, 214, 252 Emery, C., 161, 167 Endemic species, 10 Engler, A., 52, 145, 171, 176, 282, 341-342 English Hare, 29 _Ephydatia crateriformis_, 94 _Epoccus_, 167 _Erebia_, 325-326 _æthiops_, 325-326 _epiphron_, 325 _glacialis_, 326 _lappona_, 326 _Eremias_, 258 Erratics, 181-182 _Eryx jaculus_, 259 _Euphorbia hiberna_, 307 European beetles, origin of, 197 butterflies, origin of, 200 land and fresh-water mollusca, origin of, 196 mammals, origin of, 106, 193 _Eurynebria complanata_, 302 _Evotomys Nageri_, 314 Extension of range, mode of, 38 Fallow Deer, 251 Falsan, A., 66, 68-69, 71, 73 Feilden, H. W., 13, 77, 84-85, 164 Finmark, Greenland mollusca on coast of, 171 Fire-toads, origin of, 259 Fischer, P., 103 Fishes, Caspian, 224 "Flotsam and jetsam" theory, 20 Foraminifera in boulder-clay, 84 Forbes, E., 64, 101, 110, 114-115, 171, 288, 339 Forest-Bed an inter-glacial deposit, 70 corresponding to continental inter-glacial deposits, 120 fauna of, 232-234 mollusca, 212-213 Fossil glaciers, 220 Fresh-water faunas, origin of, 177 _Fringilla_, 293 _cœlebs_, 293 _madeirensis_, 293 _montifringilla_, 293 _spodiogenys_, 293 _teydea_, 293 Frog, introduction of, into Ireland, 30-31 Gadow, H., 139 Galapagos Islands, 19 _Galeodes_, 270 _Gammaracanthus relictus_, 179 Gardner, J. S., 145 _Garnieria_, sub-genus of _Clausilia_, 48 _Gasterosteus aculeatus_, 92 Gaudry, A., 73, 273 Geikie, Sir A., 116, 309