312 THE AMERICAN NATURALIST. [VOL XXXII. 
gave a phylogeny of the Mammalia, which showed that his latest views 
coincided with those here expressed, and that he recognized the force of 
Baur’s criticisms cited below. 
Baur in 1886 dissented from Cope’s specific conclusion, but 
committed himself to the theory of indirect reptilian origin of 
the mammals, by substituting the term Sauro-mammalia for 
Huxley’s Hypotheria, and placing the Theromorpha as parallel, 
rather than ancestral, to the Mammalia. 
Professor Baur’s paper of 1886, “ Ueber die Kanäle im Humerus der 
Amnioten,” demonstrated that the known Theromorpha are much too 
specialized to be regarded as ancestors of the mammals, as Professor Cope 
supposed. To the hypothetical group which gave origin to both Theromorpha 
and Mammalia Baur gave the name Sauro-mammalia, expressing a similar 
view in his essay of 1887, “ Ueber die Abstammung der Amnioten Wirbel- 
thiere,” Gesell. f. Morph. u. Physiologie, München, 1887. In his recent 
paper (1897), showing that the pelycosaurs are highly specialized reptiles, 
Baur, however, gave his strong adherence to the theriodont ancestry as 
follows: “ We are fully convinced that among these South African forms, 
one of which (Tritylodon) was for a long time considered a mammal, we 
have those reptiles which might be considered as ancestral to the mammals, 
or at least closely related to their ancestors. Further finds and careful 
critical observations have to decide this.” ! 
The writer, in his university lectures of 1896, advocated the same view, 
having been strongly impressed during the previous year with Professor 
Seeley’s descriptions of Cynognathus and the Gomphodontia. 
Osborn,” in 1888, selected the Upper Triassic mammals 
Dromatherium and Microconodon as types of the mammalian 
order Protodonta, with teeth transitional between those of 
reptiles and mammals. Subsequently, in 1893,? he accepted 
Baur’s view, deriving both the Promammalia and Theromorpha 
from Permian Sauro-mammalia. 
In fact, Cope long diverted our attention from these South 
African theromorphs, which as originally perceived by Owen 
in 1876 are full of mammalian analogies, to the pelycosaurs 
1 On the Morphology of the Skull of the Pelycosauria, and the Origin of the 
mmals. By G. Baur and E.C. Case. Zoological Club, University of Chicago, 
Fobra 10; also Science, April 9, 1897, pp- 592-594. 
n the Structure and Classification of the Mesozoic Mammalia. Journ. Acad. 
Nat. ity p- 251, Philadelphia, 1888. 
3 Rise of the Mammalia in North America. Proc. Am. Assoc. Adv. Sci., p- 188, 
1893. 
