XIV LIST OF ILLUSTRATIONS. 



Page. 

 Fig. 7:;. — Peromyscua sonoriensis deserticola. Anterior upper molar of three 



individuals, showing changes in the form of the enamel patterns 



i hie to wear , 394 



74. — Peromyscus sonoriensis deserticola. a, Hindfoot; b, tail 395 



75. — Peromyscus sonoriensis deserticola. Skull, a, Dorsal view; b, 



ventral view ; c, lateral view 395 



76. — Peromyscus sonoriensis deserticola. Crowns of molar teeth, a, 



Upper scries; b, lower series 396 



77. — Peromyscus sonoriensis medius. Skull 398 



78. — Peromyscus sonoriensis dementis. Skull.... 400 



79. — Peromyscus leucopus. a, Forefoot; b, hindfoot; c, tail 403 



80. — Peromyscus mearnsii. Skull, a, Dorsal view; b, ventral view; c, 



lateral view 404 



81. — Peromyscus mearnsii. Crowns of molar teeth, a, Low T er series; h, 



upper series 404 



82. — Peromyscus texanus. Skull, a, Dorsal view; b, ventral view; c, 



lateral view 405 



83. — Peromyscus texanus. Crowns of molar teeth, a, Lower series; b, 



upper series 405 



84. — Peromyscus tornillo. Skull, a, Dorsal view; b, ventral view; c, 



lateral view 408 



85. — Peromyscus tornillo. Crowns of molar teeth, a, Lower series; b, 



upper series 409 



86. — Peromyscus arizonse. Skull, a, Dorsal view ; b, ventral view; c, 



lateral view 410 



87. — Peromyscus arizona?. Crowns of molar teeth, a, Upper series; b, 



lower series 411 



88. — Peromyscus boylii. Skull and teeth of type, a, Skull, dorsal view; 



b, crowns of lower molars; c, crowns of upper molars 415 



89. — Peromyscus boylii pinalis. Skull and teeth, a, Skull, dorsal view; 



b, ciowns of lower molars; c, crowns of upper molars 418 



90. — Peromyscus boylii pinalis. Lower surface of hindfoot 418 



91.— Peromyscus boylii penicillatus. Skull of type, a, Dorsal view; b, 



ventral view ; c, lateral view 422 



92. — Peromyscus boylii penicillatus. Crowns of molar teeth of type. 



a, Lower series; b, upper series 42.'! 



93. — Peromyscus martirensis. Skull, a, Dorsal view; 6, ventral view; 



c, lateral view 426 



94. — Peromyscus martirensis. Crowns of molar teeth, a, Low r er series; 



b, upper series 42(i 



95. — Peromyscus Stephens! Skull, a, Dorsal view; b, ventral view; c, 



lateral view 428 



96. — Peromyscus stephensi. Crowns of molar teeth, a, Lower series; b, 



upper series 428 



97. — Peromyscus californicus insignia. Skull, a, Dorsal view; b, ven- 

 tral view; c, lateral view 430 



98. — Peromyscus californicus insignia. Crown of molar teeth, a, Lower 



series; b, upper series 430 



99. — Peromyscus eremicus. a, Hindfoot; b, tail 432 



100. — Peromyscus eremicus. Skull, a, Dorsal view; 6, ventral view; 



c, lateral view 4.'!.'! 



101. — Peromyscus eremicus. Crowns of molar teeth, o, Lower series; 



b, upper series 433 



