Chap. III. 



THE1K VARIATION. 



91 



who lias given a table of the average period of their denti- 

 tion, which proves that there is a difference of no less than 

 six months in the appearance of the permanent incisors. The 

 period of gestation, from observations made by Tessier on 

 1131 cows, varies to the extent of eighty-one days; and what 

 is more interesting, M. Lefonr affirms "that the period of 

 gestation is longer in the large German cattle than in the 

 smaller breeds." 58 With respect to the period of conception, 

 it seems certain that Alderney and Zetland cows often become 

 pregnant earlier than other breeds. 59 Lastly, as four fully 

 developed mammae is a generic character in the genus Bos, 60 

 it is worth notice that with our domestic cows the two rudi- 

 mentary mammae often become fairly well developed and 

 yield milk. 



As numerous breeds are generally found only in long- 

 civilized countries, it may be well to show that in some 

 countries inhabited by barbarous races, who are frequently 

 at war with each other, and therefore have little free commu- 

 nication, several distinct breeds of cattle now exist or for- 

 merly existed. At the Cape of Good Hope Leguat observed, 

 in the year 1720, three kinds. 61 At the present day various 

 travellers have noticed the differences in the breeds in 

 Southern Africa. Sir Andrew Smith several years a^o 

 remarked to me that the cattle possessed by the different 

 tribes of Caffres, though living near each other under the 

 same latitude and in the same kind of country, yet differed, 

 and he expressed much surprise at the fact. Mr. Andersson 

 has described 62 the Damara, Bechuana, and Namaqua cattle ; 

 and he informs me in a letter that the cattle north of Lake 

 Ngami are likewise different, as Mr. Galton has heard is also 



58 'Ann. Agricult. France,' April, 

 1837, as quoted in 'The Veterinary,' 

 vol. xii. p. 725. I quote Tessier's obser- 

 vations from Youatt on Cattle, p. 

 527. 



59 ' The Veterinary,' vol. viii. p. 

 681, and vol. x. p. 268. Low's 

 ' Domest. Animals, &c.,' p. 297. 



60 Mr. Ogleby, in ' Proc. Zoolog. 

 Soc.,' 1836, p. 138, and 1840, p. 4. 

 Ijuatrefages quotes Philippi (' Revue 



des Cours Scientifiques,' Feb. 12, 1688, 

 p. 657), that the cattle of Piacentino 

 have thirteen dorsal vertebrae and ribs 

 in the place of the ordinary number 

 of twelve. 



61 Leguat's Voyage, quoted by 

 Vasey in his ' Delineations of the Ox- 

 tribe,' p. 132. 



62 ' Travels in South Africa,' pp. 

 317, 336. 



