200 DB. C. J. FORSYTH MAJOK ON MIOCEKE SQUIRRELS. [Feb. 28, 



seems to be coming to me from tbe very side from wbich it was 

 least expected. 



Schlosser in his turn has, in his elaborate and valuable Mono- 

 f!jrapbs\ taken trituberculism as his g^iide for tracing the phylogeny 

 of various orders of Mammalia. He states his ground to be as 

 follows : — " We have but to start from the perfectly recognized 

 primitive type and to trace the modifications which it has under- 

 gone"-. This perfectly recognized primitive type is, according to 

 Schlosser, tbe tritubercidar type of upper molars, and the tuber- 

 culo-sectoiial type of lower molars. Accordingly, in the diagram 

 placed by him at the head of the Monograph of Carnivora^ this form 

 of molar type is attributed to the supposed first true Carnivore. 



In accordance with the theory, Schlosser considers Mesonycc 

 or SarcotJiraustes to be the primitive type of Carnivora '. With the 

 same inexorable logic all Ungulates are dei-ived from carnivorous 

 Mammalia ; the Condylarthi'a being considered as intei-mediate 

 between the Ungulata and Creodouta'. 



I have not to deal with Carnivora on this occasion, so that I \\ill 

 only mention incidentally that, in my eyes, amongst recent Car- 

 nivoi'a, the Subursi (and, so far as the form of molars is concerned, 

 Ailurus) approach nearest to the primitive carnivorous Mammalia, 

 whilst some of the Arctocyonidae are the most primitive of Creo- 

 donta. 



Further objections may be made when Schlosser considers with 

 Cope a rather complicated form of inferior molar — the tuberculo- 

 sectorial type — to be a primitive form, and when it is assumed that, 

 whilst the upper molars become fin-ther modified by addition, the 

 lower molars from quinquetubercular become quadritubercular in 

 progress of time, by tbe loss of an anterior cus]), the paraconid. 

 The tuberculosectorial type is, in its turn, derived from a simpler 



1 M. Schlosser, " Beitriige ziir Keuutniss der Staminesgeschichte der Hiif 

 thiere und Versuch eiuer Systematik der Paar- uiid Unpaarbufer," Morpholog. 

 Jahrbucli. xii. 1887, pp. 1-136 ;— w/. " Die Aifeu, Lemuren, Chiropteren, lusecti- 

 voren, Marsupialier, Creodonten und Caniivoren des europaischen Tertiars 

 und deren Beziehungen zu ihreu lebenden und fossilen aussereuropaischen 

 Verwandten," I.-III., Wien, 1887-1890 (Beitrage z. Paliiontologie Oesterreieh- 

 Ungarns, Bd. vi.-viii.) ; — id. "Ueber die Beziehungen der ausgestorbenen Sauge- 

 thierfaimen und ihr Vcrhaltniss zur Saugethierfauna der Gegenwart," Biolog- 

 isches Centralblatt, Ed. viii. no. 19, Dee. 1888, pp. 582-631. 



- " Es handelt sich nur darum, TOn dera ■wohlerkanuten Grundtypus auszu- 

 gehen und alle Veriindeningen zu verfolgen, welcher derselbe fahig ist," Die 

 Affen, &c. ii. p. 9 (233). 



■' Id. ib. p. 4 (228). 



' " Wenn wir von der Voraussetzung ausgehen — und hiezu sind wir auch 

 Tollauf bereehtigt— dass der Ohcrkicfer-JMolar der Greodonta urspriinglieh den 

 Trituberculartypus in voUster Eeinheit gezeigt habe, so niiissen wir Mcaoni/.v 

 oder Sarcofhraiisffs unbediugt als den Urtypus betrachten. wenigstens fiir jene 

 Formen, deren obere Molaren mit ruiidJichcii ITuckern versehen sind. Es 

 SL-hliessen sich diese Typen niehr an die Kaubbeutler als an Bklcliihi/a an," 

 Die Affen, Lemuren, etc. i. p. 161. 



^ ". . . es kann keinem Zweifel unterliegen, dass alle Hufthiere von Fleiscb- 

 fressern abstammen. wobci ehcn die Condylarlhien das Zwischenstadiuni 

 reprasentirea " — M. ScUosBer, Ausgestorbene Siiugethierformeu, /. c. p, iJ85. 



