152 



STERILITY PEOM 



Chap. XVIIL 



occurring elsewhere in England, and the event must be very rare, for an 

 instance in Germany has been thought worth recording. 18 In Paraguay 

 the native Nasua, though kept in pairs during many years and perfectly 

 tamed, has never been known, according to Kengger, to breed or show 

 any sexual passion; nor, as I hear from Mr. Bates, does this animal, or 

 the Cercoleptes, breed in the region of the Amazons. Two other planti- 

 grade genera, Procyon and Gulo, though often kept tame in Paraguay, never 

 breed there. In the Zoological Gardens species of Nasua and Procyon 

 have been seen to couple ; but they did not produce young. 



As domesticated rabbits, guinea-pigs, and white mice breed so abun- 

 dantly when closely confined under various climates, it might have been 

 thought that most other members of the Eodent order would have bred 

 in captivity, but this is not the case. It deserves notice, as showing 

 the capacity to breed sometimes goes by affinity, that the one native 

 rodent of Paraguay, which there breeds freely and has yielded successive , 

 generations, is the Cavia aperea ; and this animal is so closely allied to the 

 guinea-pig, that it has been erroneously thought to be the parent-form. 19 

 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, chin- 

 several times. This latter animal 



how 



(Dasyprocta aguti) 



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 ( Coelogenys 



pacct) 



The common hare when confined has, I believe, never 



bred in Europe ; 20 though, according to a recent statement, it has crossed 

 with the rabbit, I have never heard of the dormouse breeding in confine- 

 ment. But squirrels offer a more curious case: with one exception, no 

 species has ever bred in the Zoological Gardens, yet as many as fourteen 

 individuals of S. palmar um were kept together during several years. The 

 8. cinerea has been seen to couple, but it did not produce young ; nor has 

 this species, when rendered extremely tame in its native country, Ijprth 

 America, been ever known to breed. 21 At Lord Derby's menagerie squirrels 

 of many kinds were kept in numbers, but Mr. Thompson, the superin- 

 tendent, 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 con- 

 finement. But the species which has bred more than once in the Zoological 

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

 the flying squirrel (Sciuropterus volucella) : it has, also, bred several times 



is Wiegmann's '"Arehif fiir 



gesch./ 1837, s. 162. 



Natur- is now positively denied, yet Dr 



19 Eengger, ' Saugethiere/ &c, s. 276. 

 On the parentage of the guinea-pig, 

 see also Isicl. Geoffroy St. Hilaire, ' Hist. 

 Nat. Gen.' 



the existence of the 



* 



Leporides, as described by Dr. Broca 

 ('Journal de Phys./ torn. ii. p. 370), 



20 Although 



Pigeaux ('Annals and Mag. of Nat. 

 Hist./ vol. xx. ? 1867, p. 75) affirms that 

 the hare and rabbit have produced 



hybrids. 



21 < Quadrupeds of North America, 

 by Audubon and Bachman, 1846, p. 

 268. 



s 



