ON SPECIES, HYBRIDS, AND VARIETIES. 



163 



same primeval origin. Many of the Simiae, more different among each 

 other than the Orang and Chimpanzee, Buffon regards as mere varie- 

 ties : and so, also, with respect to other animals ; but upon the same 

 untenable premises. That distinct species will often breed together, and 

 produce offspring, is certain : in some rare cases, perhaps, this hybrid 

 progeny may be fertile inter se ; and, even if it be so, the fertility of the 

 offspring is no demonstrative proof of the common origin of both parents. 

 It may be regarded as a safe proposition, that hybrids, or the progeny of 

 two parents, each distinct as to species, never, or very rarely, occur among 

 animals in a state of nature. A few solitary instances are on record, with 

 respect to insects ; and a doubtful case has been noticed among birds, in 

 the Tetrao hybridus, of Norway ; supposed, by some naturalists (without 

 much reason), to be a hybrid, between the male Capercailzie (Tetrao uro- 

 gallus), and the female of the Black Grouse (Tetrao tetrix).* But, these 

 very rare instances apart, it is only among animals diverted, or, it may 

 be said, distorted, from a state of nature, with their instincts impaired by 

 domestication, and placed, by man, under circumstances preventing the 

 natural direction of their impulses or affections, or constraining, or inducing, 

 an artificial union, that the intercourse of different species takes place ; thus, 

 the Lion and female Tiger, caged together, have produced a hybrid progeny. 



* There is no longer any doubt respecting the character of the Tetrao hybridus; it is a distinct 

 species, intermediate, in form, between the Capercailzie and Black Grouse, though much more 

 nearly allied to the former. Its scarcity, where both the other species are abundant, and its inter- 

 mediate appearance, seem alone to have excited the suspicion of naturalists, as to its being a hybrid . 

 See Mr. Yarrell's observations, in Proceedings Zool. Soc. 1831, p. 73. 



