Chap. III. THE1K VAEIATION. 91 



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

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

 Bix 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. Lefour affirms "that the period of 

 o^estation 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 mammas 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 ago 

 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 

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



58 'Ann. Agricult. France,' April, des Cours Scientifiques,' Feb. 12, 1688, 

 1837, as quoted in 'The Veterinary,' p. 657), that the cattle of Piacentino 

 vol. xii. p. 725. I quote Tessier's obser- have thirteen dorsal vertebrae and ribs 

 vations from Youatt on Cattle, p. in the place of the ordinary number 

 527. of twelve. 



59 ' The Veterinary,' vol. viii. p. 61 Leguat's Voyage, quoted by 

 681, and vol. x. p. 268. Low's Vasey in his ' Delineations of the Ox> 

 ' Domest. Animals, &c.,' p. 297. tribe,' p. 132. 



60 Mr. Ogleby, in ' Proc. Zoolog. 62 'Travels in South Africa,' pp. 

 Soc.,» 1836, p. 138, and 1840, p. 4. 317, 336. 



Quatrefages quotes Philippi (' Revue 



