76 Merriam — Descriptions of Ten New Kangaroo Rats. 



broadly spreading outwanl as spectahilis; maxillary aroli inodcrMte, with 

 well developed anjjle (often " hooked " ) ; color jialer, grizzled l)utty, nioi^t 

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

 {■20 nun.) or absent altogetlicr; distal }4 of upper surface black and 

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



Mt'd.'^tireuK'iits. — Ty^je si)ecinien ( cJ' ad.): total length, :^>:^>0; tail verte- 

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

 318; t.iil vertebra-, 107;' hind foot, 48.5. 



Dipodomys platycephalus sp. nov. 



Type from Calmalli, Lower California, Mexico. No. L")0,SS2, o" ad., 

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

 1*)05, 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 nimioltis but skull ])eculiar. 



Color. — Groun<l color ochraceous buff" moderately lined with dark hairs; 

 ankle same color (not <lusky). 



Cranial characters. — Skull in general like that of inerriami but ixtraor- 

 dinarilji hroinl; maxillary arches of zygomata broadly and squarely 

 spreading* (as in Ferodipus streatori); frontoj>arietaI shield exceedingly 

 broad; interparietal area broad; mastoid 1)u11h' normal. 



liernarks. — So far as now known, T). jilati/cejjjialus lias only one near 

 relative, insularis, from San Jose Island on the (iulf side of bower Cali- 

 fornia. It diff'ers from insularis externally in being darker (more liber- 

 ally intermixed with black hairs) and lia\ing the tail cre.st 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 insulaj-is in larger size, nuich broader 

 frontoparietal shield, and decidedly larger mastoid bulhe. 



Measurements. — Type specimen ( c? ad.): total length, 2:!S; tail verte- 

 bra', 145; hind foot, 38. Skull of type: occijnto-nasal length, ."U; breadth 

 across mastoids, 2'.\.'); lateral* sjjread of maxillary arches, 21. 



Dipodomys margaritae sp. nov. 



Tyjje from INIargarita Island, Lower California. No. 14(>,0.")8, c?yg. ad., 

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

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



Range. — Margarita Island. 



Characters. — Size very small (nearly as small -d^e.rllis); color pale jiink- 

 Lsh buff' almost ochraceous buff", moderately lined with dark hairs. Tail 

 crest small and weak; niider-stripe continuous; lateral wliite stripes 

 reaching nearly to tij) of vertebra'. Ground color similar to arcnlragns 

 but less pure — obscun-d by intermixture of dark hairs. 



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

 ably small bulhe, rather broad frontoparietal shield and intermastoid, 



• The most broiully spreading imixilUiry arches are in No. l;!'J,S70, from San .Vndres. 



