Chap. XVIII. CHANGED CONDITIONS. 135 



that it has been erroneously thought to be the parent form. 20 In 

 the Zoological Gardens, some rodents have coupled, but have never 

 produced young ; some have neither coupled nor bred ; but a few 

 have bred, as the porcupine more than once, the Barbary mouse, 

 lemming, chinchilla, and agouti (Dasyprocta aguti) several times. 

 This latter animal has also produced young in Paraguay, though 

 they were born dead and ill-formed ; but in Amazonia, according 

 to Mr. Bates, it never breeds, though often kept tame about the 

 houses. Nor does the paca (Ccelogenys paca) breed there. The 

 common hare when confined has, I believe, never bred in Europe ; 

 though, according to a recent statement, it has crossed with the 

 rabbit. 21 I have never heard of the dormouse breeding in confine- 

 ment. But squirrels offer a more curious case : with one exception, 

 no species bas bred in the Zoological Gardens, yet as many as 

 fourteen individuals of S. palmarum were kept together during 

 several years. The S. cinera has been seen to couple, but it did 

 not produce young ; nor has this species, when rendered extremely 

 tame in its native country, North America, been ever known to 

 breed. 22 At Lord Derby's menagerie squirrels of many kinds were 

 kept in numbers, but Mr. Thompson, the superintendent, told me 

 that none had ever bred there, or elsewhere as far as he knew. 

 I have never heard of the English squirrel breeding in confinement. 

 But the species which bas bred more than once in the Zoological 

 Gardens is the one which perhaps might have been least expected, 

 namely, the flying squirrel (Sciuroptems volucella) : it has, also, 

 bred several times near Birmingham ; but the female never pro- 

 duced more than two young at a birth, whereas in its native 

 American home she bears from three to six young. 23 



Monkeys, in the nine-year Beport from the Zoological Gardens, 

 are stated to unite most freely, but during this period, though 

 many individuals were kept, there were only seven births. I have 

 heard of only one American monkey, the Ouistiti, breeding in 

 Europe. 24 A Macacus, according to Flourens, bred in Paris ; and 



20 Rengger, ' S'dugethiere,' &c, s. Leporides, as described by Dr. Broca 

 276. On the parentage of the guinea- ('Journal de Phys.,' torn. ii. p. 370), 



pig, see also Isid. Geoft'roy St.-Hilaire, has been positively denied, yet Dr. PL 



' Hist. Nat. Gen.' I sent to Mr. H. geaux (' Annals and Mag. of Nat. 



Denny of Leeds the lice which I col- Hist.' vol. xx., 1867, p. 75) affirms that 



lected from the wild aperea in La the hare and rabbit have produced 



Plata, and he informs me that they hybrids. 



belong to a genus distinct from those " ' Quadrupeds of North America, 



found on the guinea-pig. This is by Audubon and Bachman, 1846, p. 



important evidence that the aperea is 268. 



not the parent of the guinea-pig ; and *• Loudon's ' Mag. of Nat. Hist..' 



is worth giving, as some authors erro- vol. ix., 1836, p. 571 ; Audubon and 



neously suppose that, the guinea-pig Bachman's 'Quadrupeds of North 



since being domesticated has become America,' p. 221. 



sterile when crossed with the aperea. 24 Flourens, ' De l'Instinct,' &c, 



21 Although the existence of the 1845, p. 88. 



