INDEX. 779 



Rivers, analogy of, to islands, 181. 



Koacb, briglitness of the male during breeding-season, 386. 



Robbery, of strangers, considered honorable, 133. 



Rol>ertson, Mr., remarks on the development of the horns in the 

 roebuck and red-deer, 265. 



Robin, pugnacity of the male, 408; autumn song of the, 420; 

 female singing of the, 420; attacking other birds with red in their 

 plumage, 408; young of the, 547. 



Robinet, on the difference of size of the male and female cocoons 

 of the silk-moth, 315. 



Rodents, uterus in the, 43; absence of secondary sexual characters 

 in, 247; sexual differences in the colors of, 609. 



Roe, winter changes of the, 619. 



Rohfs, Dr., Caucasian features in negro, 190; fertility of mixed 

 races in Sahara, 195; colors of birds in Sahara, 557; ideas of beauty 

 among the Bornuans, 663. 



RoUe, F., on the origin of man, 3; on a change in German families 

 settled in Georgia, 223. 



Roller, harsh cry of, 421. 



Romans, ancient, gladiatorial exhibitions of the, 139. 



Rook, voice of the, 426. 



Rossler, Dr. , on the resemblance of the lower surface of butterflies 

 to the bark of trees, 353. 



Rostrum, sexual difference in the length of, in some weevils, 235. 



Royer, Madlle., mammals giving suck, 186. 



Rudimentary organs, 12; origin of, 26. 



Rudiments, presence of, in languages, 102. 



Rudolphi, on the want of connection between climate and the color 

 of the skin, 219. 



Ruff, supposed to be polygamous, 248; proportion of the sexes in 

 the, 280; pugnacity of the, 409; double moult in, 443, 445; duration 

 of dances of, 460; attraction of the, to bright objects, 469. 



Ruminants, male, disappearance of canine teeth in, 60, 641 ; 

 generally polygamous, 246; suborbital pits of, 604; sexual differences 

 of color in, 6il. 



Rupicola crocea, display of plumage by the male, 448. 



Riippell, on canine teeth iu deer and antelopes, 586. 



Russia, numerical proportion of male and female births in, 

 243. 275. 



Euticilla, 525. 



RQtmeyer, Prof., on the physiognomy of the apes, 60; on tusks of 

 miocene boar, 593; on the sexual differences of monkeys, 640. 



Rutlandshire, numerical proportion of male and female births 

 in, 274. 



Sachs, Prof. , on the behavior of the male and female elements in 

 fertilization, 252. 



Sacrifices, human, 108. 



Sagittal crest in male apes and Australians, 636. 



Sahara, fertility of mixed races in, 195; birds of the, 519; animal 

 inhabitants of the, 557. 



Sailors, growth of, delayed by conditions of life, 34 ; long- 

 sighted, 38. 



Sailors and soldiers, difference in the proportions of, 36. 



