Following Rutimeyer, we have:-
Bos primigenius.
This magnificent, well known species was domesticated in Switzerland during the Neolithic period; even at this early period it varied a little, having apparently been crossed with other races. Some of the larger races on the Continent, as the Friesland, etc., and the Pembroke race in England, closely resemble in essential structure B. primigenius, and no doubt are its descendants. This is likewise the opinion of Nilsson. Bos primigenius existed as a wild animal in Caesar's time, and is now semi-wild, though much degenerated in size, in the park of Chillingham; for I am informed by Professor Rutimeyer, to whom Lord Tankerville sent a skull, that the Chillingham cattle are less altered from the true primigenius type than any other known breed. (3/38. See also Rutimeyer 'Beitrage pal. Gesch. der Wiederkauer' Basel 1865 s. 54.)
Bos trochoceros.
This form is not included in the three species above mentioned, for it is now considered by Rutimeyer to be the female of an early domesticated form of B. primigenius, and as the progenitor of his frontosus race. I may add that specific names have been given to four other fossil oxen, now believed to be identical with B. primigenius. (3/39. Pictet 'Palaeontologie' tome 1 page 365 2nd edition. With respect to B. trochoceros see Rutimeyer 'Zahmen Europ. Rindes' 1866 s. 26.)
Bos longifrons (or brachyceros) of Owen.
This very distinct species was of small size, and had a short body with fine legs. According to Boyd Dawkins (3/40. W. Boyd Dawkins on the British Fossil Oxen 'Journal of the Geolog. Soc.' August 1867 page 182. Also 'Proc. Phil. Soc. of Manchester' November 14, 1871 and 'Cave Hunting' 1875 page 27, 138.) it was introduced as a domesticated animal into Britain at a very early period, and supplied food to the Roman legionaries. (3/41. 'British Pleistocene Mammalia' by W.B. Dawkins and W.A. Sandford 1866 page 15.) Some remains have been found in Ireland in certain crannoges, of which the dates are believed to be from 843-933 A.D. (3/42. W.R. Wilde 'An Essay on the Animal Remains, etc. Royal Irish Academy' 1860 page 29. Also 'Proc. of R. Irish Academy' 1858 page 48.) It was also the commonest form in a domesticated condition in Switzerland during the earliest part of the Neolithic period. Professor Owen (3/43. 'Lecture: Royal Institution of G. Britain' May 2, 1856 page 4. 'British Fossil Mammals' page 513.) thinks it probable that the Welsh and Highland cattle are descended from this form; as likewise is the case, according to Rutimeyer, with some of the existing Swiss breeds. These latter are of different shades of colour from light- grey to blackish-brown, with a lighter stripe along the spine, but they have no pure white marks. The cattle of North Wales and the Highlands, on the other hand, are generally black or dark-coloured.
Bos frontosus of Nilsson.
This species is allied to B. longifrons, and, according to the high authority of Mr. Boyd Dawkins, is identical with it, but in the opinion of some judges is distinct. Both co-existed in Scania during the same late geological period (3/44. Nilsson in 'Annals and Mag. of Nat. Hist.' 1849 volume 4 page 354.), and both have been found in the Irish crannoges. (3/45. See W.R. Wilde ut supra; and Mr. Blyth in 'Proc. Irish Academy' March 5, 1864.) Nilsson believes that his B. frontosus may be the parent of the mountain cattle of Norway, which have a high protuberance on the skull between the base of the horns. As Professor Owen and others believe that the Scotch Highland cattle are descended from his B. longifrons, it is worth notice that a capable judge (3/46. Laing 'Tour in Norway' page 110.) has remarked that he saw no cattle in Norway like the Highland breed, but that they more nearly resembled the Devonshire breed.]
On the whole we may conclude, more especially from the researches of Boyd Dawkins, that European cattle are descended from two species; and there is no improbability in this fact, for the genus Bos readily yields to domestication.