Cyamidæ, 56; habits, 224 _Cyclops_, 40; nauplius, 82; habits, 170; resting stage, 171; as host of Guinea-worm, 252 _Cymothoa_, 220 Cymothoidæ, habits, 218 Cymothoinæ, habits, 220 _Cypris_, 38; reproduction, 172 Cypris stage of Barnacles, 84; of _Sacculina_, 233 _Cystisoma_, 145 _Cythereis_, 38 _Daphnia_, 38; development, 81; habits, 165; in plankton of lakes, 168 Darwin, C.: on fresh-water fauna, 157, 159; on habits of _Birgus_, 198, 199; on Barnacles used for food, 237 Decapoda, 57; fossil, 267 Deep-water Prawn, 246 Delage, Y., on development of _Sacculina_, 232 Development of Lobster, 28; of Crayfish, 77; of River Crab, 78; of Peracarida, 78; of Woodlice, 79; of Opossum Shrimp, 79; of Cladocera, 80; of Ostracoda, 81; of Copepoda, 82; of fresh-water Crustacea, 160; of Epicaridea, 223; of parasitic Copepoda, 225, 227, 230; of Rhizocephala, 232 _Diaptomus_, 170 _Diastylis_, 49 Diatoms, 139; relation to Mackerel fishery, 251 _Dichelaspis_, 209 Digestive gland, 17 Dispersal of fresh-water Crustacea, 159; of Crayfishes, 174 Distribution of Woodlice, 206 Doflein, F., on luminosity in marine animals, 126 Dogfish, Barnacle parasitic on, 235 _Dorippe_, 95 _Dracunculus_, 252 _Dromia_, 63; habits, 96; and Sponge, 215 Dromiacea, 63; of deep Sea, 128, 134 Dublin Prawn, 33; fishery, 240 _Ebalia_, 63; protective resemblance, 109 Écrevisse, 242 Edelkrebs, 242 Edible Crab, 64, 248 Eggs of Lobster, 27; of deep-sea Crustacea, 130; of fresh water Branchiopoda, 161 Endopodite, 11 _Engæus_: distribution, 177; habits, 179, 189 Entoniscidæ, 223 Ephippium of Cladocera, 167 Epicaridea, habits, 221 Epiplankton, 143 Epipodite, 11 Epistome, 62 _Erichthus_ larva, fossil, 266 _Eryon_, 135 Eryonidea, 60; eye-stalks of, 122; luminosity, 126; eggs of, 131; fossil and living species, 133, 268 _Estheria_, 36; habitats, 161 Eucarida, 56 Eucopepoda, 41 Eumalacostraca, 45 _Eupagurus_, 91; commensals, 213 Euphausiacea, 56; larvæ, 76; of deep sea, 124, 125; luminous organs, 125, 151; eyes, 153; fossil, 263 European Lobster, 32 _Eurydice_, 219 Evolution, 256 Excretory organs, 19 Exopodite, 10 Exoskeleton, 15 Eyes of Lobster, 20; of _Cyclops_, 40; of deep-sea Crustacea, 121; of plankton Crustacea, 151; of _Bythotrephes_, 169; degeneration in subterranean Crustacea, 186 Eye-stalk of Lobster, 14 Fairy Shrimp, 35; habitats, 161 _Filaria_, 252 Fiddler Crab: habits, 106; colour-change, 111 Fish: attacked by Isopods, 219; Crustacea as food of, 250 Fish-lice, 224 Flagellum, 14 Foraminifera, 118 Fossil Crustacea, 256 _Galathea_, 130 Galatheidea, 60