MAMMALS OF MINNESOTA. 217 



An acquaintance of mine after this tells me that his Indian, in 

 this way repeatedly called the musquash within reach of his 

 paddle in the moonlight, and struck at them." Thoreau. The 

 Maine Woods, p. 211. 



FAMILY DIPODID^E. 



This is an interesting, though not a large, family containing 

 five genera of springing mice distributed over widely separated 

 regions of the earth. The three subdivisions included under 

 this head are so diverse that there is considerable difference of 

 opinion as to their relative rank. The affinities assumed for 

 the animals included in them are borne out by external resem- 

 blances more fully than by anatomical structure. Alston gives 

 the following diagnosis of the family : ' ' Incisors compressed. 

 Premolars present or absent. Grinding teeth rooted or root- 

 less, not tuberculate, with more or fewer transverse enamel - 

 folds. Skull with the brain-case short and broad, infraorbital 

 opening rounded (often as large as the orbit) ; zygomatic arch 

 slender; curved downward ; the malar ascending in front to the 

 lachrymal in a flattened perpendicular plate ; facial surface of 

 the maxillaries minutely perforated ; mastoid portion of the 

 auditory bullas usually greatly developed. Metatarsal bones 

 greatly elongated, often fused into a cannon-bone. Form slen- 

 der ; front portion of the body and fore limbs very small ; hind 

 limbs long and strong, with from three to five digits ; tail 

 long, hairy." 



Three subfamilies, viz : (Jaculince=) 1. Zapodince, 2. Dipo- 

 dince, and 3. Pedetince. The last named departs most from the 

 murine or mouse-like character, and contains a single genus 

 and species found in South Africa. The animal is figured at 

 the left in the headpiece to Rodentia. It is of nearly the size 

 of a rabbit, and but for the long and densely hairy tail, would 

 much resemble one. The fore feet are rather larger than those 

 of allied forms, while the nails upon the posterior extremities 

 are almost hoofs. The cervical vertebras are free as are the 

 metatarsals. 



The Dipodince form three genera, Dipus, Aladaga and Platy- 

 cercomys. 



The first named genus contains the jumping mice of Europe 

 and northern Africa, while the second inhabits the steppes of 

 Asia and European Russia. These animals have the cervicals 



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