36 THE AMERICAN BISONS. 
longer and thicker horn-cores. In respect to the American forms, three 
stages are represented, each later form being not only smaller than the pre- 
ceding, but the reduction in the size of the horn-core is relatively greater 
than that of general size. 
The types here recognized as distinct forms under the names B. priscus 
and B. antiquus, it should be remarked, differ but slightly from each other, — 
not more so, probably, than do B. bonasus and B. americanus, if indeed so 
much, —and constitute as it were a common circumpolar form from which 
B. bonasus and B. americanus have probably been differentiated. It seems 
to me that the B. americanus is really the most differentiated form, B. bonasus, 
in its more massive frame and rather larger horns, more strongly recalling 
the preceding links (Bison antiquus and B. priscus) in the chain. It was also 
until recently the form apparently farthest from extinction. For centuries 
the B. bonasus has had but a few hundred survivors, while its total extermi- 
nation has been prevented only through royal protection; the B. americanus, 
on the other hand, still has millions of representatives, and a few decades ago 
swarmed in immense herds over nearly a third of the North American conti- 
nent. 
6. — DESCRIPTION OF THE EXISTING SPECIES. 
BISON AMERICANUS (Gme.rin) Siru. 
American Bison or Buffalo. 
Bos americanus GMELIN, Syst. Nat., I, 204, 1788. Desmarest, Nouv. Dict. Hist. Nat., II, 531, 1816 ; 
Mammalogie, 496, pl. xliv, 1820. —HarLan, Fauna Amer., 268, 1825. Gopman, Amer. Nat. Hist., 
II, 4, 1826.— Desmovttn, Dict. Class. Hist. Nat., II, 365, 1822. — Rrcnarpson, Fauna Bor. Amer., 
I, 279, 1829. — Fiscuer, Synop. Mam., 495, 653, 1829. — Cooper, Month. Am. Journ. Geol. & Nat. 
Hlist., 1831, 44, 174, 207 (remains at Big-bone Lick, Ky.); Amer. Journ. Sci., XX, 371, 1831; Edinb. 
New Phil. Journ., XI, 353, 1831.— Doucury, Cab. Nat. Hist., II, 169, pl. xiv, 1832. — Sasine, Frank- 
lin’s Journey, 668, 1833. — Waanmr, Schreber’s Siiuet., V, 472, 1855. — GieBEL, Siugt., 271, 1855. 
— Barrp, Mam. N. Amer., 682, 1857; U.S. & Mex. Bound. Survey, Pt. II, 52, 1859. — Newnerry, 
Pacif. R. R. Expl. & Surveys, VI, iv, 72, 1857. — Sucxiny & Grpzs, Ibid. XII, ii, 138, 1860. — 
Xantus, Zool. Garten, I, 109.— ALLEN, Proc. Bost. Soc. Nat. Hist., XIII, 186, 1869; XVII, 39, 1874. 
Bison americanus Catespy, Nat. Hist. Carolina, II, App., 20, xxviii, 1754. — Brisson, Reg. Anim., 
Quad., 1756. — Situ, Griffith’s Cuv., V, 374, 1827. De Kay, Nat. Hist. New York Zool., Pt. I, 
110, 1842. — Sunpevatt, Kong. Sv. Vet. Akad. Handl. for 1844, 203, 1846. — Gray, Knowsley’s 
Menag., 49, 1850; Cat. Mam. Brit. Mus., Pt. III, 39, 1852; Hand-List of Edentate, Thick-Skinned, 
& Ruminant Mam., 85, 1873. —-Gerrarp, Cat. Bones of Mam. Brit. Mus., 230, 1862. — TURNER, 
