210 [December, 



think any one will grant who will take the trouble to compare the figures of 

 the " Siberian crania," in the works of Pallas,* Ozeretskovsky,f or Cuvier,J 

 with my figures of Bootherium cavifro?is. The former are indistinguishable 

 from the figures given of the crania of the recent Ovibos moschatus, while the 

 latter has no deep fissure separating the bases of the horn cores, but these are 

 confluent and form a huge process covering the entire length and breadth of the 

 frontal bone. 



Sir John Richardson has himself, in page 22 of his work, considered the " Si- 

 berian crania" as belonging to the Ovibos moschatus ; and in the above extract 

 has stated there 13 " no reasonable doubt of the fossil species," [Bootherium cavi- 

 frons) ''being quite distinct from the recent one" [Ovibos moschatus). Conse- 

 quently, he has decided that Bootherium is a different animal from the species to 

 which the " Siberian crania" belonged. Therefore, it appears to me, when Sir 

 J. R. subsequently says, " A question now arises whether the dentata above 

 referred to as the foundation of th supposed palaeozoic species Ovibos maximus, 

 may not be a relic of Dr. Leidy's cavifrons, and this might, without much risk of 

 mistake, be decided in the affirmative, were it certain that the Siberian crania 

 mentioned in the ' Ossemens Fosslles' were identical in species with those em- 

 bedded in the drifts of the Mississippi, but as yet the evidence of such an ex- 

 tension of the ancient range of cavifrons is wanting," the question had 

 already been decided that " the Siberian crania" were not "identical in species 

 with those embedded in the drifts of the Mississippi." 



Sir J. R. then says, te The size of Dr. Leidy's specimen of cavifrons does not 

 exceed that of the skull of an aged musk-bull, and the dentata of maximus is of 

 corresponding dimensions." If this be the case I would ask, as the li dentata of 

 maximus " was found in the country of the " musk-bull," and is of the same size 

 as the corresponding bone in that animal, what evidence is there that it does not 

 belong to it ? 



Under these circumstances "the discovery of a dentata of the musk-ox type, 

 and of suitable size, in the valley of the Mississippi," would by no means " estab- 

 lish the identity of cavifrons with maximus" but would rather tend to show the 

 greater ancient range of the Ovibos moschatus. 



In regard to the time at which the appellations cavifrons andmaximus were 

 made,public I deem it of trifling importance to science, but I may take the pre- 

 sent opportunity of stating that the name Bootherium cavifrons was proposed in 

 the number of the Proceedings of this Academy for May and June 1852, which 

 was distributed the following month, therefore three months previous to the ap- 

 pearance of the " first part of the Herald's Zoology." 



In conclusion I may add a list of what appear to be the species of American 

 ox, recent and extinct. 



1. Bison Americanus, (recent and fossil). The fossil certainly not the Bison 

 priscus ? Richardson. 



2. Bison latifrons, Leidy. For synonyma refer to page 8 of Mem. on Ext. 

 Sp. of Am. Ox., and add Sus Americamis, Harlan ; Harlauus Americanus } Owen. 



3. Bison priscus? Richardson. 



4. Bison crassicornis, Richardson. 



5. Bison antiquus ? Leidy. I think not the same as the Bison crassicornis, 

 Richardson, but probably it may be Bison latifrons. 



6. Bootherium cavifrons, Leidy. Syn. page 12 of Mem. on Ext. Sp. &c. 



7. Bootherium bombifrons, Leidy. Syn. page 17 of Mem. on Ext. Sp., &c, 

 and add Bison bombifrons, Richardson, Zool. Her. p. 41. 



8. Ovibos moschatus. (Recent and fossil.) Bos Pallassii, De Kay. 



9. ? Ovibos maximus, Richardson. 



* Nov. Com. Petrop. xvii., tab. xvii , figs. 1 3. 



f Mem de 1' Acad, de St. Petersb., iii., pi. vi. 



% Ossem. Foss. ed. 4, vi., pi. clsxii., figs. 9, 10, clxxi. figs. 6, 7. 



See Proc. Acad. Nat. Sci. vii. 89. 



