THE HOG TRIBE. 



19 



" It is possible that some of the caudal vertebrae may be missing. 



" The Chinese was imported into this country for the purpose of 

 improving our native sorts, with which it breeds freely, and the off- 

 spring are again fruitful. I, this winter, saw a fine litter of pigs by 

 Sir Rowland Hill's African 6oar, imported with the female I describ- 

 ed, the mother of which was a common pig time will show whether 

 they will be again fruitful. 



" From what has been stated, the result appears to me to be, that 

 either of the above three pigs must be considered as distinct species, 

 (and which, should the offspring of the two latter again produce 

 young, would do away with the theory of Hunter, that the young 

 of two distinct species are not fruitful,) or we cannot consider osteo- 

 logical character a criterion of species. 



" I have been induced to offer the above, not with any desire of 

 species-making, but of adding something towards the number of 

 recorded facts, by which the question what is a species, must be 

 answered." 



Closely-allied species may produce offspring fertile inter se, although 

 we have no proof positive of the fact in the case in question ; for 

 when domestication produces decided differences of external form, 

 why should it be difficult to admit of the extension of the differ- 

 ences to internal parts also, and especially to the osseous frame- 

 work, on which the form and symmetry of the body so greatly depend, 

 or why the law of variation should be confined in its influence to 

 one part, and restricted from another. If it be admitted that the 

 bones may be somewhat modified in length or stoutness, we see not 

 why it is that a numerical variation in the bones of the vertebral 

 column should be so great a stumbling-block, especially seeing that 

 accidental (and perhaps hereditary) variations are far from being 

 uncommon, both in men and others of the mammalia. We can 

 easily conceive that a portion of the osseous system, offering in al- 

 most every species of quadruped some variation in the number of 

 its constituent parts, should be also the most likely to exhibit such 

 variation, where a species long subjected to the modifying influence 

 of human control, has branched out into various breeds or 



