76 Merriam Descriptions of Ten New Kangaroo Rats. 



broadly spreading outward as spectabilis; maxillary arch moderate, with 

 well developed angle (often " hooked ") ; color paler, grizzled buffy, most 

 intense on flanks and rump, with vinaceous tinge ; white tip of tail shorter 

 (20 mm.) or absent altogether; distal % of upper surface black and 

 tufted; lateral white tail stripes reaching about % length of tail. 



Measurements. Type specimen ( & ad.): total length, 330; tail verte 

 bra?, 204; hind foot, 50. Average of 10 from type locality: total length, 

 318; tail vertebra?, 197; hind foot, 48.5. 



Dipodomys platycephalus sp. nov. 



Type from Calmalli, Lower California, Mexico. No. 139,882, cT ad., 

 U. S. National Museum, Biological Survey Collection. Collected Oct. 1, 

 1905, by E. W. Nelson and E. A. Goldman. Original No. 18,248. 



Range. Western Lower California from San Andres south to Santa 

 Domingo and easterly over the arid desert to Calmalli. 



Characters. Similar externally to merriami simiolus but skull peculiar. 



Color. Ground color ochraceous bnff moderately lined with dark hairs; 

 ankle same color (not dusky). 



Cranial characters. Skull in general like that of merriami but extraor 

 dinarily broad; maxillary arches of zygomata broadly and squarely 

 spreading* (as in Perodipus streatori); frontoparietal shield exceedingly 

 broad; interparietal area broad; mastoid bullse normal. 



Remarks. So far as now known, D. platycephalus has only one near 

 relative, insularis, from San Jose Island on the Gulf side of Lower Cali 

 fornia. It differs from insularis externally in being darker (more liber 

 ally intermixed with black hairs) and having the tail crest more sooty 

 (instead of brownish). 



The young (from San Andres) are decidedly darker than young from 

 San Jose Island. 



The skull differs from that of insularis in larger size, much broader 

 frontoparietal shield, and decidedly larger mastoid bullse. 



Measurements. Type specimen ( cT ad.): total length, 238; tail verte 

 brae, 145 ; hind foot, 38. Skull of type: occipi to-nasal length, 34; breadth 

 across mastoids, 23.5; lateral spread of maxillary arches, 21. 



Dipodomys margaritae sp. nov. 



Type from Margarita Island, Lower California. No. 146,058, cT yg. ad., 

 . U. S. National Museum, Biological Survey Collection. Collected l)ec. 1, 

 1905, by Nelson and Goldman. Original No. 18,711. 



Range. Margarita Island. 



Characters. Size very small ( nearly as small asexilis); color pale pink 

 ish buff almost ochraceous buff, moderately lined with dark hairs. Tail 

 crest small and weak; under-stripe continuous; lateral white stripes 

 reaching nearly to tip of vertebrae. Ground color similar to arenivagus 

 but less pure obscured by intermixture of dark hairs. 



Skull. Very small and light with slender rostrum and nasals, remark 

 ably small bullse, rather broad frontoparietal shield and intermastoid, 



* The most broadly spreading maxillary arches are in No. 139,870, from San Andres. 



