MURIDE. — CLNXXY. 319 
1036 b. Z. insignis Miller. Larger than Z. Audsonwus, with 
longer ears and paler, more fulvous coloration, tail with white tip: 
molars $3. L.10. T. 6. In deep woods, Penn. and N. Y. to 
Nova Scotia. (Lat., distinguished.) 
Famiry CLXXXIV. GHOMYIDAS. (THE PovcHEp 
GOPHERS.) 
Cheek pouches large and distinct, opening outside of the mouth. 
Molars $$; incisors large and thick ; skull heavy ; temporal bones 
enormously developed. Limbs about equal, the fore claws five in 
number, very large; tibia and fibula united. Body thick-set and 
clumsy. Genera 2; many species; all North American, and chiefly 
inhabiting the central plains; habits subterranean. Farther west 
occur numerous species of Heteromyide or Pocket Mice, smaller 
than the Gophers, and with thin and papery skulls. 
a. Upper incisors, each with « large groove near the middle; ears rudi- 
mentary; fore claws enormous. . . . . Gerowrys, 540. 
aa. Upper incisors not grooved ; ears distinct but very small; claws 
moderate... . 2. ws +. + . + « » THomomys, 541. 
540. GHOMYS Rafinesque. (7, earth; pis, mouse.) 
1037. G. bursarius (Shaw). Pocket GopHer. Reddish 
brown, with plumbeous tinge ; upper incisors with two grooves, the 
larger near the middle line; tail and feet hairy. L.11. T. 3. 
Prairies, Wis., IL, and W. to S$. Dak. and Neb. (Lat., pouched.) 
541. THOMOMYS Maximilian. (@wpds, heap; pis. mouse.) 
1038. TT. talpoides (Richardson). NorTHERN Pocket Go- 
PHER. Dusky plumbeous; tail, feet, and breast mostly white , 
ears inaduskyarea. L.94. T. 2. Minn. to Plains and N. W. 
(Lat., like a mole.) 
Famiry CLXXXY. MURIDAX, (Tue Mice.) 
Incisors 3; molars usually $:$; anteorbital foramen a vertical 
slit, widening above and bounded externally by a broad plate of 
the upper maxillary; coronoid and condyloid processes of lower 
jaw well developed. Tibia and fibula united below. Genera 
about 80. A large family, found in all parts of the globe, some 
of the species (Mus) being cosmopolitan, having accompanied man 
in all his migrations: all are of small size, the incerat being one 
of the largest. and some are smaller than any other quadrupeds, 
except the Shrews. 
a. Tacisors broad, often broader than deep: molars rooted or rootless with flat 
crowns and re-entrant angles (body heavy, eyes small, snout blunt, legs 
