1886. ] Geology and Paleontology. 721 
divisions based on their structure, e. g., Condylarthra, Ambly- 
oda, “ Paar- und Unpaarhufer.” Within each of the latter he 
admits bunodont and lophodont forms. It is in the Condylarthra 
that he hesitated to admit the lophodont form Meniscotherium, 
and is disposed to place it in the Perissodactyla on account of its 
dentition; a proceeding in which we cannot agree with him. It 
is considerations derived from the dentition that lead Dr. Schlos- 
case with the Bovide, in which Dr. Schlosser regards the robust 
form Bos as the descendant of the slender Gelocus. Such has 
Probably been the history of Rhinocerus, which Dr. Schlosser 
objects to deriving from Hyrachyus on account of the more 
slender feet of the latter. 
€re is an important discussion as to the origin of the milk 
dentition (p. 109). Dr. Schlosser refers to Baume’s hypothesis 
that the temporary dentition consists of those teeth which have 
en thrown out of the regular series by the contraction of the 
regular series. A preferable hypothesis is that of Wortman, 
which regards the mammalian dentition as following a law of 
Succession fundamentally that of the reptilian, the reduction con- 
sisting in nothing but anteroposterior members.! 
add that Elasmotherium is much more probably derived from 
Ccelodonta than from Aphelops. Also that the American Elo- 
therium has but two metapodial bones, like the European. Also- 
t the reviewer’s illustrated articles in the AMERICAN NATURAL- 
IST are mostly of later date than the Vol. 11 Report U.S. Geol, _ 
Survey Terrs,—Z. D. Cope. a 
_, GEorocicaL News.—General—M. E. Jourdy has found spiri- 
fers in the marble of the delta of Tonkin (Tonquin, Tong-king) _ 
_ and therefore concludes~ that this marble, which occurs both in 
Tonkin and Annam, is of Carboniferous age. At Dong-Songhe _ 
___ *System of Dentistry, Philadelphia, 1886, a t 
