Reviezv of Recent Geological Literature. 379 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
Phylogcny of the Rhinoceroses of Europe. By Henry Fairchild Os- 
, jBORN. {Bull. Am. Mils. Kat. Hist., -vol. xiii., article xix., pf>. 229- 
267, I goo.) 
Sonic Xciv and Lit'te Kiiorcn Fossil J'ertehrates. By J. B. Hatchf.h. 
(Annals, Carnegie .Museum, z'ol. i, 1901. pi. 1-4.) 
The RhinocerotidcC liuvc hitheto baffled the taxonomist, and their 
origin, development and migration are still problematic. The phylogeny 
proposed by Mr. Osborn divides the rhinoceroses into six phyla, hav- 
ing no known relation to each other. The supposed stem forms arc 
traced back to the early Cenozoic, therebj- suggesting that the rhinocer- 
oses, like numerous other mammalian phyla, come under the law of 
early divergence. 
Mr. Osborn bases his classification upon the i)n)portions of the 
skull and correlated proportions of the body and upon the location of 
the horn cores. He finds these to be the main divergent characters, 
setting aside several homoplastic characters licrctoforc employed in 
classification. 
Besides suggesting a liypothesis of descent, Mr. Osborn offers some 
interesting systematic and comparative descriptions, based upon the 
study of the collections in various European museums. 
Mr. Hatcher's paper is based upon material collected by the pale- 
ontological expedition of igoo, for which Mr. Andrew Carnegie sup- 
plied the funds. He describes Trigonias osborni, a new genus of rhi- 
noceros, from the base of the White River Oligocene. The manus 
differs from all other known American rhinoceroses in being function- 
ally tetradactyl ; it has an uni;educed number of superior teeth : and 
simple structure of the superior premolars. It is therefore of a gen- 
eralized type, and is the most primitive member of the Rhinoceroted?e 
at present known. ' 
The comparison with the unreduced teeth of Trigonias will make 
possible the establishment of the homology of the teeth of the modern 
rhinoceroses. Trigonias probably represents the ancestral form of one 
of Mr. Osborn's six groups, the Accrathcriinae. i. h. <>. 
