EXPLANATION OF PLATES. 



61 



PLATE XXII. 



Fig. l—Sperm(ypMlus grammurus, Bacli.— No. 1111.— Copper Mines, New Mexico.— Skull 



natural size. Keferences a-e. 



Fig. 2—SpermopMlus mexicanus,L\cht.—'No. 1267.— Brownsville, Texas.— Skull natural size. 



References a-e. 



Fig. SSpermojpJiilus spilosoma, Bennet. — No. 1323.— El Paso.— Skull.— a-e, natural size;/— 



left upper molars from below ; g — left lower molars from above ; f-g, rather 

 more than twice natural size. 



PLATE XXIII. 

 Fig. 1 — Geomys clarkii, Baird. — No, 162i. — Presido del Norte. Skull. — a-e, natural size; /■ 



from 



nearly three times. 



/ 



Fig. 2— Bipodomys agilis, Gsimhel. — No. 1630. — Monterey, Cal.— Skull, a-e, natural size; /- 



left upper molars from below ; g — left lower molars from above ; h — front view of 

 upper incisors ; f-h^ magnified a little more than twice. 



■ 



Fig. 2—Dipodomys ordii^ Woodhouse.— No, 1632.— Western Texas.— Skull. References a-h^ 



as in the last figure. 

 Fig. 4 — Dipodomys ordii^ var, montanus. — No* 1631.— Upper Rio Grande valley, a — left 



upper molars from below ; h — left lower molars from ahove ; c — front view of 



upper incisors. Magnified about twice. 



Fig. 5 — Thomoinys umhnmis J Bssird. — No. 1231. — Sonora, — Skull, References a~g as in fig. 1 ; 



yand g magnified nearly three times. 

 Fig. 6 — Perognathus Mspidus^ Baird. — No. 1696. — Female. — Charco Escondido, Mexico, 



Skull. References a-g^ as in fig. 1 ; f-g magnified rather more than twice. 



PLATE XXIV. 



Fig. 1 — Neotoma mexicana^ Baird. — No. 260. — Colorado bottom. — Skull, a — from below ; 



h — from above ; c — from the side ; d — left side of lower jaw ; e — do. from above ; 

 all of natural size ; / — left upper molars from below ; g — left low^er molars from 



/ 



Mexico. — Skull. 



Fig, 2 — Neotoma micropuSj Baird. — No. 1676. — Male, 



References a-g, as in the preceding figure ; / and g magnified nearly three 



times. 

 Fig. 3 — Sigmodonberlandieri J Balvd. — No. 1667. — Coahuila, Mexico. — Skull, References a-^; 



as in figure 1 ; /and g magnified nearly three times. 



Fig. 4 — Beithrodon megahlis, Baird. — No. 2281. — Janos to San Luis Spring, New Mexico. 



Skull. References a-j^j as in fig. 1 ; f-g magnified nearly three times. 



PLATE XXY. 



r 



Fig. 1—Lepus caUolis, var. Jlavogularis?~^o. 1215.— San Antonio to El Paso.— Skull natural 



mzQ. References a-e. 



