1!)1U.] TupuiiiUi: Skull, Ossicula auditus, Vertebrce.. 275 



any marked specializations, and parallels that of Mtjrmecobius. The eoro- 

 noid is delicate, the angle hook-like and slightly inturned, and the condyle 

 transverse but not much extended. The jaws figured by Anderson (Yunnan 

 Expedition, pi. vii) vary considerably in the different species, and this 

 variability is likewise shown in the position of the mental foramina which 

 are usually below ])3 and P4, but sometimes below c and p,. 



In Ptilocenis, in correlation with greater powers of mastication and the 

 diprotodont modification of the incisors the lower jaw is shorter and stouter 

 especially anteriorly, and the coronoid process and the fossa for the temporal 

 muscles are larger and better developed (Fig. 21). 



Ossicula auditus. According to Doran (1S79, p. 442) the malleus of 

 Tupaia, "in being neckless and devoid of lamina. . . .much resembles that 

 of some of the lower Primates, especially Midas or Hapalc, or certain Lemurs, 

 the shallow articular facets being a Ceboid feature. The incus has a high 

 and narrow body and in general characters is "very like the same in many 

 Monkeys and Lemurs." The stapedial crura are straight (they are curved 

 in Lipotyphla). The stapes is pierced by a bony canal (as in Lipotyphla). 



The vertebral formula, as determined from a skeleton of Tupaia sp. in the 

 National Museum is C. 7, D. 13, L. 6, S. 3, Cd. 26; as determined from de 

 Blainville's figures of Glisorex (Tupaia) ferrugineus it is C. 7, D 13, L 7, 

 S 2, Cd. 23. Mivart, however (1867, p. 294), states that there are only 5 or 6 

 lumbars, so that the dorsolumbars appear to vary (DL 18-20). This 

 formula compares with that of ])rimitive forms in other groups as follows^: 



hi its vertebral formula Tupaia is thus evidently very ])riniitive, more so 

 than most other Insectivores. 



In correlation with the non-fossorial, climbing habits, the sacrum is 



1 The table is based upon data given in Bronn's ' Thierreich ' (pp. 240-252) and by Leche 

 ( 1907, p. 77.) 



