Miller Seven New Rats collected in Siam. 149 



Teeth. The teeth are relatively broader than in Mas jerdnni, but in 

 structure they show no peculiarities. 



Measuremerds. External measurements of type: total length, 400; head 

 and body, 197; tail, 203; hind foot, 38 (36); ear from meatus, 2l!o; ear 

 from crown, 18; width of ear, 15. Ten specimens (five of each sex) from 

 the type locality average: total length, 372 (356-400); head and body, 187 

 (162-197); tail vertebra, 185.5 (175-203); hind foot, 38.6 (36-40); hind foot 

 without claws, 35.8 (34-39). 



Cranial measurments of type: greatest length 46 (36.6)*; basal length, 

 40 (30); basilar length, 37 (27.6); palatal length, 19 (14.8); least width of 

 palate between anterior molars, 4.6 (3.8); diastema, 13.4 (9.4); length of 

 incisive foramen, 7.4 (6.6); combined breadth of incisive foramina, 4 (3); 

 length of nasals, 18.6 (14); combined breadth of nasals, 5 (3.6); zygomatic 

 breadth, 19.8 (15.4); interorbital breadth, 7.6 (6); mastoid breadth, 15 

 (13); breadth of braincase above roots of zygomata, 16 (15); depth of 

 braincase at front of basioccipital, 12 (10.4); frontopalatal depth at pos 

 terior extremity of nasals, 9 (8); least depth of rostrum immediately be 

 hind incisors, 8 (6.8); maxillary toothrow (alveoli), 7 (6); width of front 

 upper molar, 2 (1.6); mandible, 24.6 (18.6); mandibular molar series 

 (alveoli), 7 (5.8). 



Specimen* <'.<'<iniined. Twenty-one, all from the type locality. 



Remarks. Mm xurifer is somewhat closely related to Mu# jerdoni, 

 though immediately distinguishable by its much greater size. Two 

 adult specimens of the latter measure: total length, 325 and 322; head 

 and body, 200 and 192: tail vertebra, 125 and 130; hind foot, 31.5 (30.5) 

 and 30.5 (29.5); ear from meatus, 19 and 19; ear from crown, 16 and 16; 

 width of ear, 14 and 13. Externally MM surifer is probably much like 

 the Bornean Mus rajah Thomas; but the skull is considerably smaller. 

 Some of the cranial measurements of the type of Mus rajah are: greatest 

 length, 51; basilar length, 41; zygomatic breadth, 22; nasals, 19; dias 

 tema 14.5 



*Measurements in parenthesis are those of an adult specimen of Mus 

 jerdoni from Mount Mooleyit, Burmah. 



