dy, ii. 306, 312;
Tarroo, ii. 157.
SILK-MOTHS, i. 300-304;
domesticated species of, i. 300;
history of, _ibid._;
causes of modification in, i. 300-301;
differences presented by, i. 301-304;
crossing of, ii. 98;
disease in, ii. 228;
effects of disuse of parts in, ii. 298;
selection practised with, ii. 197, 199;
variation of, ii. 236;
parthenogenesis in, ii. 364.
SILKWORMS, variations of, i. 301-302;
yielding white cocoons, less liable to disease, ii. 336.
SILVER-GREY rabbit, i. 108, 111, 120.
SIMONDS, J. B., period of maturity in various breeds of cattle, i. 87;
differences in the periods of dentition in sheep, i. 96;
on the teeth in cattle, sheep, &c., ii. 322;
on the breeding of superior rams, ii. 196.
SIMON, on the raising of eggs of the silk-moth in China, ii. 197.
SIMPSON, Sir J., regenerative power of the human embryo, ii. 15.
_Siredon_, breeding in the branchiferous stage, ii. 384.
SISKIN, breeding in captivity, ii. 154.
_Sivatherium_, resemblance of the, to Niata cattle, i. 89.
SIZE, difference of, an obstacle to crossing, ii. 101.
SKIN, and its appendages, homologous, ii. 325;
hereditary affections of the, ii. 79.
SKIRVING, R. S., on pigeons settling on trees in Egypt, i. 181.
SKULL, characters of the, in breeds of dogs, i. 34;
in breeds of pigs, i. 71;
in rabbits, i. 116-120, 127;
in breeds of pigeons, i. 163-165;
in breeds of fowls, i. 260-266;
in ducks, i. 282-283.
SKULL and horns, correlation of the, ii. 333.
SKYLARK, ii. 154.
SLEEMAN, on the Cheetah, ii. 151.
SLOE, i. 345.
SMALL-POX, ii. 378.
SMITER (pigeon), i. 156.
SMITH, Sir A., on Caffrarian cattle, i. 88;
on the use of numerous plants as food in South Africa, i. 307.
SMITH, Colonel Hamilton, on the odour of the jackal, i. 30;
on the origin of the dog, i. 16;
wild dogs in St. Domingo, i. 28;
on the Thibet mastiff and the alco, i. 28-29;
development of the fifth toe in the hind feet of mastiffs, i. 35;
differences in the skull of dogs, i. 34;
history of the pointer, i. 42;
on the ears of the dog, ii. 301;
on the breeds of horses, i. 49;
origin of the horse, i. 51;
dappling of horses, i. 55;
striped horses in Spain, i. 58;
original colour of the horse, i. 60;
on horses scraping away snow, i. 52;
on _Asinus hemionus_, ii. 43;
feral pigs of Jamaica,