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Show 198 DR. C. J. FORSYTH MAJOR ON MIOCENE SQUIRRELS. [Feb. 28, pronounced unfavourably on the theory since it was first brought forth, and the same is the case, so far as I a m 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-intemal cusp in the upper molars of the Mammalia are homologous with the reptilian cone and with each other "!. Trituberculism, or, as w e rather ought to call it, the reptilian-cone theory, 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 was invented2; since that time I have kept silent for various reasons. M y intention is not to deal fully with the subject on this occasion ; 1 wish only to present a few general remarks on what I consider to be weak points of the theory, and then to enter on more particulars so far as the Sciurine type of molars is concerned. 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 Vertebrates3, the most numerous being the Condylarthra with 23, and the Creodonta with 50 species'. I have already stated that, according to Cope, amongst 82 Puerco Mammalia only four are quadrituber-culate, all the rest being trituberculate. N o w it appears to m e 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, the 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-dontidae, showing a relatively simple type of molar, were richly represented; hence it was concluded that this was the primitive type of the ungulate molar. Riitimeyer has recently strongly insisted upon the fact that the Carnivorous Mammalia of the Egerkingen fauna, the same which has yielded numerous remains of Lophiodontidae, are exceedingly poorly represented, the remains of Ungulata being more than twenty times in excess of those of Carnivora6. In the Puerco, on the other hand, where we have an analogy to the Egerkingen0 fauna in regard to primitive types, 1 Osborn and Wortman, " Fossil Mammals of the Wahsatch and Wind Kim- Beds, Collection of 1891," Extr. from Bulletin of the American Museum of Nat. Hist. iv. no. 1, Oct. 1892, p. 85. 2 Forsyth Major, "Nageriiberreste aus Bohnerzen Siiddeutschlands und der Schweiz. Nebst Beitriigen zu einer vergleichenden Odontographie von Ungu-laten und Unguiculateu," 1873. Palaxmtographica, xxii. a Cope, ' Synopsis Puerco Fauna,' p. 300. 4 Id, ib. pp. 304, 305. 5 L. Riitimeyer, " Die Eocane Saugethierwelt von Egerkingen," Ablinntl-lungen d. schweiz. palaontol, Ges. vol. xviii. 1891, p. 93. 0 Riitimeyer, ib. |