112 Merriam Two New Wood Rats. 



On reexamining the specimens from San Francisco Mountain 

 and comparing them with the duplicate types of N. mexicana 

 they are found to be widely dissimilar, not only in external 

 appearance, but also in cranial and dental characters. Singularly 

 enough, the new species resembles N.fuscipes of California much 

 more closely than mexicana. It is an inhabitant of the pine belt 

 at the base of the mountain, and therefore belongs to the Transi- 

 tion zone. Its range probably meets that of N. mexicana, which 

 inhabits the adjacent Painted Desert on the east and the Grand 

 Canon of the Colorado on the north. The avenue by which its 

 ancestors originally reached the pine plateau region of Arizona 

 becomes a geographic problem of no little interest. Its nearest 

 ally, the southern form of N. fusdpes, is closely restricted to 

 California, and no member of the fuscipes group has- ever been 

 reported from the Rocky Mountain region. 



Remarks on the Validity of the Genus Teonoma of Gray. 



In 1843 J. E. Gray separated the bushy-tailed wood rats gener- 

 ically from the round-tailed species under the name Teonoma* 

 In this arrangement he was followed by Fitzinger in 1867f, but 

 not by other'writers. The only character ever assigned the genus 

 Teonoma, so far as I have been able to ascertain, is its bushy tail, 

 in contradistinction to the short-haired terete tail of Neotoma 

 proper. I take pleasure, therefore, in calling attention to an im- 

 portant cranial character which seems to have been overlooked. 

 In the skulls of the round-tailed wood rats there is a long open 

 slit on each side of the presphenoid and anterior third of the 

 basisphenoid. These openings may be designated the spheno- 

 palatine vacuities. In the bushy-tailed species (Neotoma cinerca 

 and N. cinerea occidentalis) these vacuities are absent, being com- 

 pletely closed by the ascending wings of the palatine bones. 

 Whether this character is of generic or subgeneric value may be 

 left an, open question for the present ; that it is a character of 

 considerable importance cannot be denied. 



The most interesting feature connected with the new Neotoma 

 arizonas herein described is that while it agrees with Teonoma in 

 the possession of a bushy tail, it has the spheno-palatine vacui- 

 ties of Neotoma proper. 



* List of Specimens of Mammalia in the British Museum, 1843, p. 117. 

 f Sitzungsberichte Math. -Nat., Cl. K. Akad. Wiss.Wien, vol. LVI, Abth. i ? 

 1867, p. 77. 



