34 



Christmas Island, 



FOTES ON THE OSTEOLOGY OE MUS NATIVITATI8 

 AXD MUS MACLEARL 



By Dr. C. I. Eoestth Majoe, E.Z.S. 



(PLATE II, Us.) 



Eyen" if it were not known that Mus nativitatis is terrestrial and 

 burrowing, while 3Ius macleari is arboreal, the examination of the 

 manus of both species would reveal this fact at once. The bones of 

 the antebrachinm, the cai-pals, metacarpals, and proximal phalanges 



rm; 



Fig. 1. — Antebrachium and carpus of Mns macleari. 

 Fig. 2. — Antebrachium and carpus of Mus nativitatis. 



It, radius ; Z7", ulna ; r, radiale ; u, ulnare ; rm, radiale marginale ; 

 p, pisiforme ; c, centrale ; 1-4, first to fourth carpale ; a, dorsal 

 phalange of first digit ; i-v, first to fifth digit. 



are all slenderer and more elongate in the latter species, stouter 

 and broader in the former, the longitudinal dimensions of the 

 fore-limb as a whole being about the same in both. 



