1897.] 



MALAGASY GETfUS BRACHYURO.MTS. 



70^ 



same longitudinal row. Winge has summed up in a few words 

 his view of the fate of these outer cusps \ But in the figures 

 of upper Eodent molars he ignores what I consider to be their 

 homologues. Tor a clearer understanding of what is to follow, I 

 append two sketches of the same upper malar from "Winge's plates, 

 the first with the numbering given by this author, the second with 

 the numbering according to the manner in which I grasp the homo- 

 logies. The tooth figured is one of the Hesperomyince with more 

 complicated molars, being a copy of fig. 12 a, pi. iii. of ^\ inge's 

 paper '\ representing the second right upper molar of " Nectomys 

 squamipes" (text -figs. 1 and 2). Winge assigns the homologies 



Second right upper molar of NectoTnys sguamipes, after Winge. 



thus : %-r., taking into consideration only what in these teeth 

 appear to be the principal cusps ; whereas I would write them as 

 follows : — s — j^, taking into consideration as well those which 



in these teeth appear to be merely secondary cusps \_ 



Now as to Brachyuromys. Here we have as principal feature of 

 the molars three transverse and somewhat oblique rows. In 

 Bracliyuromys ramiroliitra the separation of the three rows, their 

 obliquity and their lophodontism are more pronounced than in 

 B. hetsileoensis, whose unworn teeth show a half-tuberculate con- 

 formation and are therefore more fit for the understanding of 

 the homologies. 



if. 2 Slip. (Plate XXXIX. figs. 1 a, 2 a, 3 a, 7 a, 8 «).— The 

 anterior transverse row apparently is composed of the outer 

 cusp 1 and the inner cusp 6. The second one is a compound, 

 on the outer side, of ' 4 ' anteriorly and ' 2 ' posteriorly, -which 

 in very early stages become fused with each other and with 

 the inner cusp 7. The most prominent outer and inner cusps, 



1 "Kronen bliver Ted sin Va?xt saa bred, at Underlijrebe tjenderne ere for 

 smalle til endnu at rore red dens ydre Eand, naar Munden lukkes ; derfor 

 Tantrives de tre oprindelige yderste Spidser og indskrfenkes til fremspi-ingende 

 Hjcerner eller Lister, sinelte sammen med de nsermeste iudre Spidser ellerfors- 

 Tinde belt " (Om Pattedyreues Tandskifte, etc., I. c. pp. 17, 18 ; see also footnote 4 

 on p. 41). 



^ ' Gnavere fra Lagoa Santa, etc.' 



3 On comparison of the lower molars figured in Plates XXXIX. and XL. of 

 tbe present paper with those on pi. iii. of Winge's " Om Pattedyrenes Tand- 

 skifte, etc.," it will be seen that my mode of numbering the cusps to indicate 

 their homologies disagrees with the one adopted by Winge ; but I cannot in 

 this paper enter into a discussion of my mode of viewing the homologies of 

 lower molars. 



