258 THE PRINCIPLES OF [Part II. 



We will first briefly run through the class of mammals, 

 and then turn to birds. The gorilla seems to be a polyg- 

 amist, and the male differs considerably from the female ; 

 so it is with some baboons which live in herds containing 

 twice as many adult females as males. In South America 

 the 3fycetes caraya presents well-marked sexual differ- 

 ences in color, beard, and vocal organs, and the male gen- 

 erally lives with two or three wives: the male of the 

 Cebus capucinus differs somewhat from the female, and 

 appears to be polygamous. 5 Little is known on this head 

 with respect to most other monkeys, but some species are 

 strictly monogamous. The ruminants are eminently polyg- 

 amous, and they more frequently present sexual differ- 

 ences than almost any other group of mammals, especially 

 in their weapons, but likewise in other characters. Most 

 deer, cattle, and sheep, are polygamous ; as are most ante- 

 lopes, though some of the latter are monogamous. Sir 

 Andrew Smith, in speaking of the antelopes of South 

 Africa, says that in herds of about a dozen there was 

 rarely more than one mature male. The Asiatic Ant Hope 

 saiga appears to be the most inordinate polygamist in the 

 world ; for Pallas 6 states that the male drives away all 

 rivals, and collects a herd of about a hundred, consisting 

 of females and kids : the female is hornless and has softer 

 hair, but does not otherwise differ much from the male. 

 The horse is polygamous, but, except in his greater size 

 and in the proportions of his body, differs but little from 



5 On the Gorilla, Savage and Wyman, c Boston Journal of Nat. Hist.' 

 vol. v. 1845-1847, p. 423. On Cynocephalus, Brehm, 'Illust. Thierleben,' 

 B. i. 1864, s. 77. On Mycetes. Rengger, ' Naturgesch. : Saugethiere von 

 Paraguay,' 1830, s. 14, 20. On Cebus, Brehm, ibid. s. 108. 



6 Pallas, * Spicilegia Zoolog., Fasc. xii. 1777, p. 29. Sir Andrew- 

 Smith, 'Illustrations of the Zoology of South Africa,' 1849, pi. 29, on the 

 Kobus. Owen, in his 'Anatomy of Vertebrates ' (vol. iii. 1868, p. 633), 

 gives a table incidentally showing which species of Antelopes pair and 

 which are gregarious. 



