EXPLANATION OF PLATE 28 
Dorsal view of crania of three subspecies of Aplodontia; X 0.54. Fig. 11, 
Aplodontia rufa rainieri, no. 90144, Biol. Sury. Coll.; fig. 12, Aplodontia rufa 
columbiana, no. 1899, Mus. Comp. Zool.; fig. 18, Aplodontia rufa rufa, no. 3751, 
Mus. Vert. Zool. 
Note the general similarity in size between Aplodontia rufa rainieri and A. r. 
columbiana, with the latter somewhat the larger; note the heavier zygomatic 
arch in columbiana as compared with either of its neighbors, together with the 
greater expansion of the arch near the posterior root. Note the tendency in 
rainieri and columbiana to have temporal ridges closer together than in Aplo- 
dontia rufa rufa. Note in the latter the general smaller size and lighter zygo- 
matic arch as compared with the mountain subspecies. 
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