PERODIPUS. 



MICRODIPODOPS. 



cil, the base of hairs of which are white; lateral white stripes broad 

 reaching basal part of pencil. Legs, above white, beneath dusky. 



Measurements. Total length, 275; tail vertebras, 165; pencil, 25; 

 hind foot, 42; ear from crown, S. 



365. compactus. {Dtpoiio/nys), True, Proc. U. S. Nat. Mus. Wash., 

 188S, p. 160. 



Type locality. Padre Island, Texas. 



Geogr. Distr. Known from type locality only. 



Genl. Char. Size medium; hind foot shorter than skull; tail 

 equal in length to the head and body; color pale. 



Color. Above pale pinkish buff tinged on head and back with 

 sepia; beneath white; thigh stripe white. Sides and distal half of 

 under side of tail white; upper surface, including the pencil, and 

 proximal half of under surface sepia. 



Measurements. Total length, 215; tail vertebrae, 114; hind 

 foot, 31. 



63. Microdipodops. 



Microdipodops. Merr., N. Am. Faun., 1891, Pt. 5, p. 115. 



Cranium similar to that of Dipodom\s, but with the tympano-mas- 

 toid much more inflated. Palatal shelf extending posteriorly to fora- 

 men ovale with a deep fossa on each side. Zygomatic process of 

 maxillary not expanded in front of orbit; mandible without post- 

 molar pit, and the angular process truncated. Mastoids meet along 

 median line and project posteriorly, their breadth being greater than 

 basilar length. Molars rootless; upper premolar with anterior prism. 



ftOoo yocp 



Fig 55. Microdipodops megacephalus. 

 No. 43193 Field Columbian Museum Coll. Nat. size. 



Lower tooth row. Upper tooth row. 



Enlarged lo times. Enlarged lo times. 



