APPENDIX 



Akt. XXIV. — Miocene Artiodactyles from the Eastern 

 Miohvpjpus Beds ; by O. C. Maksh. 



In recent numbers of this Journal, the writer has described 

 various ungulate mammals from the upper Miocene of South 

 Dakota and adjoining regions.* These were artiodactyles 

 mainly, and of them the larger forms were related more or less 

 closely to the genus Anthracotherium, established by Cuvier 

 in 1822. These forms prove, on further study, to be more 

 numerous and important in the horizon where Protoeeras was 

 found, or in the eastern Miohippus beds, than was at first 

 suspected, and some additional specimens are described briefly 

 and figured in the present article. 



Heptacodon gibbiceps, sp. nov. 



The type specimen of the present species is a skull in good 

 preservation, except the posterior part, which is lost. The 

 portion preserved fortunately affords a number of characters 

 sufficient to separate the genus from allied forms of the same 

 horizon, which will be discussed later. 



The facial portion of this skull is strongly rounded above, 

 especially in the frontal region, and this has suggested the 

 specific name. The orbits are large, and not closed behind, 

 although limited posteriorly by strong processes above and 

 below. There is no antorbital depression, and the lachrymal 

 foramen is inside the orbit. The nasals are elongate, narrow 

 in front, and widely expanded behind where they join the 

 frontals. They touch the lachrymals, thus separating the 

 maxillaries from the frontals. 



* This Journal, vol. xlvii, p. 409, May, 1894; and vol. xlviii, p. 91. July, 1894. 

 See also, vol. xli, p. 81. January, 1891; vol. xlvi, p. 407, plate vii, November, 

 1893 ; and vol. xxxix, p.' 524, June, 1890. 



