494 
INDEX. 
DUCKWEED. 
Duckweed, 385, 
Dngongj affinities of, 414, 
Dung-beetles with deficient tarsi, 135. 
Dyticus, 386. 
E. 
Earl, Mr. W., on the Malay Archipe¬ 
lago, 395. 
Ears, drooping, in domestic animals, 
11 . 
-, rudimentary, 454. 
Earth, seeds in roots of trees, 361. 
Eciton, 238. 
Economy of organization, 147. 
Edentata, teeth and hair, 144. 
-, fossil species of, 339. 
Edwards, Milne, on physiological divi¬ 
sions of labour, 115. 
-, on gradations of structure, 194. 
-, on embryological characters, 
418. 
Eggs, young birds escaping from, 87. 
Electric .organs, 192. 
Elephant, rate of increase, 64. 
-of glacial period, 141. 
Embryology, 438. 
Existence, struggle for, 60. 
•——, conditions of, 206. 
Extinction, as bearing on natural selec¬ 
tion, 109. 
-of domestic varieties. 111. 
-, 317. 
Eye, structure of, 187. 
■-, correction for aberration, 202. 
Eyes reduced in moles, 137. 
E. 
Fabre, M., on parasitic sphex, 218. 
Falconer, Dr., on naturalisation of 
plants in India, 65. 
-on fossil crocodile, 313. 
-on elephants and mastodons, 334. 
-and Cautley on mammals of sub- 
Himalayan beds, 340. 
Falkland Island, wolf of, 394. 
Faults, 285. 
Faunas, marine, 348. 
Fear, instinctive, in birds, 212. 
Feet of birds, young molluscs adhering 
to, 385. 
FRUIT-TREES. 
Fertility of hybrids, 249. 
-from slight changes in conditions, 
267. 
■-of crossed varieties, 268. 
Fir-trees destroyed by cattle, 72. 
-, pollen of, 203. 
Fish, flying, 182. 
-, teleostean, sudden appearance of, 
305. 
—— eating seeds, 362, 387. 
-, fresh-water, distribution of, 384, 
Fishes, ganoid, now confined to fresh 
water, 107. 
-, electric organs of, 192. 
-, ganoid, living in fresh water, 321. 
-of southern hemisphere, 376. 
Flight, powers of, how acquired, 182. 
Flowers, structure of, in relation to 
crossing, 97. 
- of compositse and umbelliferae, 
144. 
Forbes, E., on colours of shells, 132. 
—— on abrupt range of shells in 
depth, 175. 
--on poorness of palaeontological 
collections, 288. 
-- on continuous succession of 
genera, 316. 
-on continental extensions, 357. 
-, on distribution during glacial 
period, 366. 
-on parallelism in time and space, 
409. 
Forests, changes in, in America, 74. 
Formation, Devonian, 334. 
Formations, thickness of, in Britain, 
284. 
-intermittent, 290. 
Formica rufescens, 219. 
-sanguinea, 219. 
-flava, neuter of, 240. 
Frena, ovigerous, of cirripedes, 192. 
Fresh-water productions, dispersal of, 
383. 
Fries on species in large genera being 
closely allied to other species, 57. 
Frigate-bird, 185. 
Frogs on islands, 393. 
Fruit-trees, gradual improvement of, 37. 
——-in United States, 85. 
-—, varieties of, acclimatised in 
United States, 142. 
