198 DE. C, J. rOESYTIT MAJOR OX MIOCENE SQUIRRELS. [Feb. 2^, 



pronounced unfavourably on tbe tbeory since it was first brougbt 

 £ortb, and the same i-> tbe case, so far as I am aware, with biologists 

 in general. 



The cardinal point established, to use Osborn's words, is that 

 " the antero-external cusp in the lower molars and the antero-internal 

 casn in the upper molars of the Mammalia are homolof/OKS with the 

 reptilian cone and with each other '''^. 



Trituberculism, or, as we rather ought to call it, the reptilian- 

 cone tbeory, is no more a theory, but has become a dogma. I am 

 a heretic, and may say that I opposed the theory already in 

 1873, viz. before it Avas invented'; since that time I have kept 

 silent for various reasons. 



My intention is not to deal fully with the subject on this 

 occasion ; I wish only to present a iew general remarks on what I 

 consider to be weak points of the theory, and then to enter on 

 more particulars so far as the Seiurine type of molars is con- 

 cerned. 



It is but fair to begin with the Puerco fauna, the stronghold of 

 trituberculism, from the discovery of which dates the establishment 

 of the theory. In this fauna we have 106 species of Vertebrates ^ 

 the most numerous being the Condylarthra with 23, and the 

 Creodouta \\ ith o^i species '. I have already stated that, according 

 to Cope, amongst 82 Puerco Mammalia only four ai'e quadrituber- 

 culate, all the rest being trituberculate. 



Now it appears to me that the Puerco fauna, as at present 

 known, does not give us an adequate idea of what must have been 

 the Mammalian life of that period, tbe proportion of carnivorous 

 Mammalia being far too large to be a real one. So that we meet 

 here with exactly the same mode of argument which years before 

 had been resorted to with regard to the zygodont type. In the 

 oldest (then well-known) Tertiary Mammalian faunas the Lophio- 

 dontidse, showing a relatively simple type of molar, were richly 

 represented ; hence it was concluded that this was the primitive 

 type of the ungulate molar. Uiitimeyer has recently strongly 

 i)isisted upon the fact that the Carnivorous Mammaha of the 

 Egerkingen fauna, the sauie which has yielded numerous remains 

 of Lo]ihiodontida3, are exceedingly poorly represented, the remains 

 of ITngulata being more than twenty times in excess of those of 

 Carnivora ''. h\ the Puerco, on the other hand, w here we haAO 

 an analogy to the Egerkingen'' fauna in regard to primitixe types, 



1 Osboi'n and \^'ortiiian, ' Fossil Mamuials of the Wahsatcli and Wind Eiver 

 Beds, Collection uf 1891." Extr. from Eidletin of tbe American Miismim of 

 Xat. Hist. iv. no. 1, Oct. 1892, p. 8.1. 



* Forsyth Major, •' Nageriiberreste aiis Bohnerzen Siiddeutsclilands imd der 

 Schweiz. ^'ebst Beitriigen zu einer vergleichenden Odontographie von Ungu- 

 laten und Ungiiiculaten," 1S73. Palaeontograpliitxi. rxii. 



^ Cope, ' SjTiopsis Puerco Fauna,' p. 3W. 



* Id. ib. pp. S04, 30.5. 



^ L. Eiitimeyer, " Die Eocane Saugethierwelt von Egei-kingen," Abhand- 

 lungen d. schweiz. paliionto], Ge.s. vol. xviii. 1891, p. 93. 

 '' Eiitimeyer, ih. 



