Miller. fleven New Hots collected in Siam. 145 



formly backward. Zygomata light though less slender than in M. jerdoni, 

 not abruptly flaring anteriorly. Supraorbital ridges well developed and 

 continued backward to interparietal, but not forming a distinct postorbi- 

 tal angle. 



Teeth. The teeth agree closely with those of Mus jerdoni. Arrange 

 ment of molar tubercules as in M. jerdoni and M. decumanus. Anterior 

 face of incisors bright orange, the upper somewhat darker than the lower. 



Measurements. External measurements of type: total length, 317; head 

 and body, 146; tail vertebrae, 171; pencil, 8; hind foot, 30(28.5)?;* ear 

 from meatus, 17; ear from crown, 13; width of ear, 12. A second speci 

 men: total length, 305; head and body, 130; tail ver ebrae, 175; hind 

 foot, 30(28.5)?* 



Cranial measurements of type: greatest length, 34; basal length, 28; 

 basilar length, 25; palatal length, 13.4; least width of palate between 

 anterior molars, 3.4; diastema, 8.2; length of incisive foramen, 5.6; com 

 bined breadth of incisive foramina, 2.6; length of nasals, 11.8; combined 

 breadth of nasals, 4; zygomatic breadth, 15.4; interorbital breadth, 6; 

 mastoid breadth, 12.8; breadth of braincase over roots of zygomata, 

 14.8; depth of braincase at front of basioccipital, 10; fronto-palatal 

 depth at posterior extremity of nasals, 7; least depth of rostrum imme 

 diately behind incisors, 6; maxillary toothrow (alveoli), 6; width of front 

 upper molar, 1.6; mandible, 15.6; mandibular toothrow (alveoli), 6. 



Specimens examined. Two, both from the type locality. 



Remarks. Mus cremoriventer differs too widely from the other species 

 known to occur on the Malay Peninsula to require any special compari 

 son. It is immediately recognizable by its moderate size, slender form, 

 spiny fur, and long, unicolor, slightly penicillate tail. 



Mus asper sp. nov. 



Type adult female (skin and skull) No. 86,767 United States National 

 Museum, collected in the mountains of Trong, Lower Siam, at an alti 

 tude of about 1000 ft., February 2, 1899. 



Characters. Smaller than Mus jerdoni (hind foot about 28 mm). Tail 

 shorter than head and body, bicolor, but not white at tip. Fur of back 

 very densely set with stiff bristles. General color raw sienna above, dull 

 buff beneath, the^tr everywhere dusky at base] a tawny spot on chest. 

 Skull relatively broader than in Mas jerdoni or M cremoriventer, the ante 

 rior portion of the zygomata more abruptly flaring and whole arch dispro- 

 portionally heavy. 



Far. The fur is as in Mus jerdoni and M. cremoriventer, except that the 

 spines are more abundant on back and less numerous on sides and belly. 

 Back with veryfew long terete hairs. Legs wholly free from bristles. 



Color. General color above raw sienna (slightly paler than Ridgway, 

 PL V, Fig. 2) fading to light ochraceous on sides. Back, shoulders, neck, 

 and head uniformly clouded or speckled with bister; this and the raw 



^Distorted in preparation; measurement probably too long. 



