NORTH AMERICA AND THEIR VERTEBRATE FAUNA. Iig 



ancestor as are the Pelycosaurs, but as they are on the mammaUan hne, I should 

 keep them in the mammal-like phylum, and regard them as the most primitive 

 division of the Therapsida." 



In a recent paper on the genus Bolosaurus, Broom" reiterates his views 

 and presents further evidence. 



Watson, in a recent paper,*" has expressed his idea of the necessity of 

 uniting the North American and South African forms. After a detailed 

 discussion he says: 



"The final result is that the presence of the Deinocephalia makes it impos- 

 sible to exclude the American Lower Permian and Carboniferous Pelycosaurs from 

 the later South African Therapsids. Such a division could any time have been 

 drawn only on the more primitive limbs and large quadrate of the early forms; 

 the fact that in Deinocephalia we have types with a quadrate as large as that of 

 the Pelycosauria combined with modernised limbs renders the foundation of a 

 great group division on these characters quite impossible. 



" For this great stem of the Reptilia, including all the mammal-like reptiles, 

 many names are available. I am myself inclined to extend Broom's Therapsida, 

 a most appropriate name, to the whole of them, but I fully recognize that Coi^e's 

 earlier names of Theromorpha and Theromora have been used in the same sense ; 

 these names were never very clearly defined by Cope, and have at one time or 

 another included nearly all Permian reptiles. If any one should wish to resusci- 

 tate these names in this connection, I would point out to them that Owen's term 

 Anomodontia was used by that author in i860 in a wide sense to include the 

 Dicynodonts and also carnivorous Therapsids from South Africa, and has at least 

 as good a claim to be used as Cope's later terms." 



Broom and, especially, Williston insist upon the hopelessness of any 

 attempt to present a permanent classificatiori of the early reptiles at the 

 present time when only a portion of the fauna is known, and that portion, 

 in the main, forms fragmentary skeletons. It is largely in recognition of 

 the inadequacy of our information and the failure of many recently pro- 

 posed classifications by Osborn, Jaekel, and others, as I understand Dr. 

 Williston, that he proposes a return to what he considers a stable basis, and 

 proposes to unite the Pelycosauria, Protcrosauria, Caseasauria, Kadaliosau- 

 rida;, and the Therapsida as suborders under the old order Theromorpha.'' 



His classification is as follows: 



Order Theromorpha : 



Suborder Pelycosauiia. 



Family Cleps3'dropsidffi (Sphcnacodontida;). 



Family Poliosauridae. 



Family Edaphosaurida;. 

 Suborder Proterosauria. 



Family Paleohatteridse. 

 Suborder Caseasauria. 



Family Caseidas. 

 Suborder . 



Family Kadaliosaurida; ( Ara^oscelida-) . 



"Broom, Bull. Amer. Mus. Nat. Hist., vol. 32, p. 515, 1913. 

 •"D. M. S. Watson, Proc. Zool. Soc, London, vol. 1914, p. 778. 

 Williston, Jour. Morphology, vol. 23, p. 649. 



