ILLUSTRATIONS. 



PLATES. 



[Plate I, frontispiece; Plates II- VIII, following page 132.) 



Plate I. Prairie pocket gopher CThomomys talpoides rufescens). 



II. Skulls (ventral views) of Thomomys bulbivorus, T. townsendi townsendi, T. 

 bottse bottse, T. perpallidus aureus, T. talpoides rufescens, T. t. clusius, 

 T. idahoensis, T.fossor, T. monticola monticola (smd lateral view oi monti- 

 cola), T. douglasi douglasi, T. bottse leucodon, T. ocius, and T. umbrinus 

 umbrinus. 



III. Skulls (dorsal views) of Thomomys bulbivorus, T. townsendi townsendi, T. t. 



nevadensis, T. bottx bottse, T. b. leucodon, T. b. laticeps, T. b. angularis, 

 T. b. pallescens, and T. altivallis. 



IV. Skulls (dorsal views) of Thomomys bottse pascalis, T. b. minor, T. b. navus, 



T.fulvus texensis, T.f. pervagus, T. perpallidus apache, T. sinalox, T. b. 

 alticolus, and T. b. russeolus. 

 V. Skulls (dorsal views) of Thomomys perpallidus albatus, T. p. perpallidus, 

 T. p. per pes, T. operarius, T. p. aureus, T. p. canus, T. latirostris, T. caba- 

 zonx, T. alpinus awahnee, T. bottx mewa, T. b. anitx, T. magdalenx, T. a. 

 alpinus, T. jadnteus, T. neglectus, and T. b. nigricans. 

 VI. Skulls (dorsal views) of Thomomys fulvus fulvus, T. cervinus, T.f. toltecus, 

 T. mearnsi, T. f. intermedius, T. f. desertorum, T. baileyi, T. lachuguilla, 

 T. perditus, T. goldmani, T. nelsoni, T. sheldoni, T. umbrinus umbrinus, 

 T. u. peregrinv^, T. u. orizabx, and T. atrovarius. 

 VII. Skulls (dorsal views) of Thomomys talpoides rufescens, T. t. bullatus, T. t. 

 nebulosus, T. t. agrestis, T. t. clusius, T. t. caryi, T. t. pryori, T. quadratus 

 quadratus, T. ocius, T. idahoensis, T. pygmxus, T. columbianus, T. fossor, 

 T. uinta, T. bridgeri, and T. quadratus fsheri. 

 VIII, Skulls (dorsal views) of Thomomys monticola monticola, T. m. mazama, T. 



m. pinetorum, T. m. nasicus, T. douglasi douglasi, T. d. melanops, T. 

 niger, T. d. oregonus, T. fuscus loringi, T. hesperus, T, d. yelmensis^ T. 

 limosus, T.f. fuscus (male and female), T.f. my ops, and T.f. saturatus. 



TEXT FIGURES. 



Page. 



Fig. 1. Map showing distribution of the genus Thomomys 9 



2. Skins of adult females of Thomomys, showing number and position of 



mammae in different groups and species: 1, Thomomys umbrinus 

 umbrinus; 2, T. bottx bottx; 3, T. fossor; 4, T. talpoides rufescens ... 12 



3. Skins of Thomomys, showing waves of pelage during molt: 1, Thomo- 



mys talpoides rufescens; 2, 4, T. quadratus fisheri; 3, T. t. clusius 19 



4. Skins of Thomomys showing abnormal pelage conditions, due to tick 



bites, mange, or skin disease: 1, Thomomys fossor; 2, T. fuscus 

 fuscus 21 



5. Map showing distribution of certain species and subspecies of Thomo- 



mys: 1, fuscus; 2, loringi; 3, saturatus; 4, my ops; 5, columbianus; 6, 

 bridgeri; 7, uinta; 8, quadratus; 9, townsendi; 10 nevadensis; 11, canus; 

 12, monticola; 13, pinetorum; 14, mazama; 15, nasicus; 16, helleri; 

 17, bulbivorus; 18, hesperus; 19, douglasi; 20, oregonus; 21, yelmensis; 



22, melanops; 23, limosus; 24, niger 23 



5 



