Remarks upon the Theory of Hybridity. 359 



mestication has the effect of diminishing or increasing the 

 number of vertebrae. This most probably, however, is the case 

 with regard to the caudal vertebras, but not with regard to the 

 others ; as we find in dogs that, although, among those that 

 have not been mutilated, the caudal ones differ, the remainder 

 do not, in any at least that I have had opportunities of ex- 

 amining. But this will require further investigation, upon which, 

 should it still appear that domestication has not the effect of alter- 

 ing the number of any of the vertebrae except the caudal ones, 

 and, consequent^ that John Hunter's theory is not the true 

 one ; in fact, that animals, nearly allied in their organisation, 

 will breed together, and their offspring be productive; then 

 the now supposed varieties of the genus Sus will become true 

 species. 



It will, however, probably be some years before these points 

 are set at rest ; and it will require much patient investigation, 

 either to prove or disprove them. 



I cannot here help hazarding the conjecture, that the theory 

 of Hunter will be partially disproved ; and that it will be 

 found that animals of different species, nearly allied in their 

 organisation, will breed together when in a state of domestic- 

 ation, confined together, or occasionally in a wild state, under 

 peculiar circumstances ; such as has been the case among black 

 gafme in various parts of the country ; single grey hens having, 

 in several instances, bred with the common pheasant, not being 

 able to find a male of her own species : and that the hybrids 

 the produced will be productive, under any circumstances, when 

 parents are nearly allied, of the same genus, and not otherwise. 



All true hybrids that have been productive have been pro*- 

 duced from species brought from remote countries, and in (or 

 partially) a state of domestication. May we not, therefore, 

 suppose that it is a provision of Providence, to enable man to 

 improve the breeds of those animals almost necessary to his 

 existence ; and that it is almost a necessary provision, as it is 

 universally found that breeding in, as it is called, among those 

 animals that we have the opportunity of observing, tends to 

 diminish and dwindle the race which has been subjected to it? 



The above communication may, perhaps, seem uncon- 

 nected ; but this must necessarily be the case when the links 

 are wanting. My object has been to offer a few suggestions 

 relative to a subject so vitally connected with zoological, as 

 well as with geological, science. 



Being, however, desirous not to trespass too long upon 

 my reader's patience, I conclude with hoping, that those who 

 have it in their power will make public any information they 

 possess relative to the subject. 



dd 4 



