VOL. XX, PP. 75-80 JULY 22, 1907 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



DESCRIPTIONS OF TEN NEW KANGAROO RATS. 

 BY C. HART MERRIAM. 



The collections of the Biological Survey contain ten appar 

 ently undescribed species and subspecies of kangaroo rats from 

 California and Mexico the latter collected by E. W. Nelson and 

 E. A. Goldman, mainly in the course of their recent explora 

 tions on the peninsula of Lower California. Of the 10 new 

 forms, 6 belong to the genus Dipodomys and 4 to the genus 

 Perodipus. 



In working out the ranges of the various species of the group 

 I am indebted to Mr. E. A. Goldman for helpful assistance. 



Following are descriptions of the new forms: 



Dipodomys spectabilis cratodon subsp. nov. 



Type from Chicalote, Aguas Calientes, Mexico. No. 78,953 cT ad., 

 U. S. National Museum, Biological Survey Collection. Collected July 2, 

 1896, by E. W. Nelson and E. A. Goldman. Orig. No. 9734. 



Characters. Similar in general to spectabilis but skull larger largest 

 of the genus more massive, deeper vertically, with broader rostrum and 

 premaxillse, narrower interparietal area, and much broader and heavier 

 incisors. 



Measurements. Type specimen ( cT ad.): total length, 342; tail ver 

 tebrae, 217; hind foot, 54. Average of 9 from type locality: total length, 

 337; tail vertebra?, 208; hind foot, 52.5. 



Dipodomys nelsoni sp. nov. 



Type from La Ventura, Coahuila, Mexico. No. 79,439, cT ad., TJ. S. 

 National Museum, Biological Survey Collection. Collected Aug. 10, 1890. 

 Nelson and Goldman. Original No. 9998. 



Range. From Santa Rosalia, Chihuahua, to Jaral and La Ventura, 

 Coahuila, and thence to Dr. Arroyo, Nuevo Leon. 



Characters. Much smaller than spectabilis and very much larger than 

 ph illipsi group. (41 x 27 skull. ) Similar to spectabilis in general form 

 and inassiveness of skull but much smaller. 



Mastoids large; interparietal area small; mastoids actually nearly as 

 large relatively larger than in spectabilis; zygomata not so squarely or 

 17 PKOC. BIOL. Soc. WASH., VOL. XX, 1907. (75) 



