Aferriam. — Amfriran W(i(i<J liat^. 119 



The upper molar series is of more neiirly equal breadth through- 

 out, the anterior molar not being so broad relatively as in the 

 otiier groups. The postpahilal notch is usually narrow, though 

 it is broadened anteriorly in X. fu^cifirs »)'^r;-o?/.s of southern Cali- 

 fornia. The froutals increase in width but slightly from before 

 backward, never expanding abruptly behind the interorbital con- 

 striction as in the loirodon series. The anterior lobe of m - is 

 completely divided by a deep sulcus on the inner side into two 

 loops, except in /'(/•sr-/j>r'.v, in which the sulcus is relatively shal- 

 lower and more anterior in position, the division being less com- 

 j)lete than in other si:)ecies. So far a known the group is re- 

 stricted to the Upper Sonoran and Transition Zones, where it 

 ranges from southern Mexico (States of Jalisco, Michoacan, 

 Mexico, Puebla, and Vera Cruz) northward in the inteiior to 

 Colorado and northern Arizona, and along the Pacific Coast to 

 Oregon. 



(3) Neotoma daertorviii (jroiip. — Ncotoinn dc^crforinW' <in<l inter- 

 medial constitute the third group into which it is convenient to 

 divide the restricted genus. The group is not very sharply de- 

 fined, some forms of hUcnnedia coming very close to aberrant 

 forms of the leucodon series. The f rentals increase in breadth 

 gradually from before backwards, much as in the piiiclonuii group 

 — not suddenly behind the constriction as in the leinvdoii series. 

 There is no supraorbital bead in typical de>iertoruni, but intermedia 

 shows a decided tendency to the formation of such a bead. The 

 postpalatal notch is narrower than in any other division of the 

 genus. In dental characters the group resembles the lencddon 

 series, the molars being decidedly broader anteriorly than poster- 

 iorly, and m ^ being made up of three transverse loops, the an- 

 terior of which is but faintly indented bj the antero-internal 

 sulcus. The members of the group inhabit the Sonoran deserts 

 of northern Mexico and the southern United States, ranging from 

 Chihuahua and Sonora northward to northern Utah, northern 

 Nevada, and middle California. 



*Neotoma intermedia Rhoads inhabits the valleys of the coast reigou of California, 

 south of Monterey Bay. A somewhat paler form, usually more or less suffused with 

 pale ochraceus buffy, inhabits San Gorgonio Pass and the western edge of the Colorado 

 Desert. It was provisionally named gilva by Rhoads, and has just been renamed vcnusta 

 by True (in a publication received since the present paper went to press), but seems 

 hardly entitled to the distinction of a separate name. N. californica Price seems to be a 

 typical inlcrmedia. Two subspecies, albigitla Hartley from south and west Arizona, and 

 melanura nob. from Sonora, are here recognized. 



