210 SOME CHINESE VERTEBRATES. 



M . cansus they differ in smaller size, and from the recently described M. rufes- 

 cens in this and certain cranial characters as noted by Dr. J. A. Allen (1909). 

 The measurements of the two specimens as taken by the collector are : 



No. Sex. Total Length. Tail. Hind Foot. 



7130 9 193 38 31 



7131 cf 190 35 27 



The skulls show that the two specimens are nearly comparable in age, yet 

 that of the female is the smaller. Thomas has pointed out the fact that the 

 skulls of M . cansus show a sexual differentiation of a similar nature, those of the 

 males being markedly the larger. The dimensions of the two skulls follow, 

 those of the male in each case first: greatest length, 39, 37; basal length, 

 33.5, 31; palatal length, 21, 19.5; diastema, 11.3, 11.2; zygomatic breadth, 

 26.5, 24.4; interorbital constriction, 8, 8; mastoid breadth, 21.8, 18.5; median 

 length of nasals, 14.4, 13.5; mandible from condyle to tip of incisor, 27.2, 25.8; 

 upper molar row, 9.5, 8.4; lower molar row, 10, 9. 



MICROTUS MANDARINUS (Milne Edwards). 



This rare mouse is represented by six skins and skulls, three from Ramala 

 Pass (at 16,000 feet) and three from Shuowlow (13-15,000 feet), in western 

 Szechwan on the border of Tibet. Milne Edwards described this field mouse 

 from Chinese Mongolia where it was obtained by Pere David. His figure and 

 description of the exterior (Recherches hist. nat. mammiferes, 1868-74, p. 129, 

 pi. 12, fig. 4) probably refer to a highly colored specimen as none of the five 

 studied is so brightly ochraceous as he indicates, though in other respects the 

 agreement is close enough. In his figures of the teeth on plate 13, the figures 

 4c and 4d are interchanged, being the lower and upper molar series respectively. 

 All our specimens agree in color, having the dorsal surfaces a finely grizzled 

 mixture of ochraceous and black-tipped hairs, the lower surfaces gray, with 

 plumbeous bases to the hairs. The tail is short and bicolor like the body. 



The measurements in the flesh of five specimens are : - 



The skull of No. 7796 measures: total length, 23 mm.; basal length, 21; 

 palatal length, 13; zygomatic breadth, 13.6; interorbital constriction, 3.7; 



