558 



MONOGRAPI 



WRTH AMERICAN RODENTIA. 



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without appreciable constricnon of tlie neck, upon which the shoulders seem 

 to encroach ; the head is especially broad, the width across the occiput being, 

 if anything, greater than the breadth across the shoulders ; the limbs are 

 short, of approximately equal lengths, massive above the wrist and ankle ; 

 the tail is very short; the muzzle is thick and blunt; the whiskers are long 

 and stiff; the ears are of moderate size; the pelage is soft. The whole organ- 

 ization, viewed externally, indicates terrestrial and highly fossorial habits. In 

 moving, the animal carries the body low, almost sweeping the ground ; at rest, 

 the back is arched. 



The head is broad and massive, much compressed in the horizontal 

 plane (being wider than deep), and especially noticeable for the flat expanse 

 of its upper surface, which is continuous with that of the shoulders without 

 depression of the nape, and with scarcely any constriction of the sides of the 

 neck behind the ears. Viewed from above, the sides of the head taper 

 gradually, in nearly straight lines, from the broadest point (at the ears) to the 

 snout, which is extremely obtuse. The profile of the forehead is likewise 

 nearly straight. The chin is retreating ; its under surface is nearly flat ; 

 the end is broadly convex, like the rest of the obtuse muzzle. The opening 

 of the mouth appears contracted from the thickness of the swollen fleshy 

 lips. The .upper incisors are probably always exposed. The peculiar shape 

 of the head as a whole is correlated with the remarkable preponderance of 

 planes and right lines which the skull shows.' 



The thick lips are entirely hairy, the upper lip especially being clothed 

 with short, stiffish, antrorse, adpressed hairs for some distance within the 

 apparent buccal orifice, and there being a special brush of similar hairs 

 directed inward, near the commissure of the lips. There is a narrow naked 

 muffle, cleft with a well-marked vertical line of impression ; a naked pad 

 projects from this to the interspace between the upper incisors ; a narrow 

 margin around each nostril is also naked ; othe'rwise the snout is entirely 

 hairy. The whiskers are numerous, very long, and extremely stiff — more 

 like hog's bristles than the whiskers of most Rodents. The longest ones, 

 when laid backward, reach entirely beyond the shoulders. These bristles 

 are mostly colorless; some of the shorter upper ones, however, are brownish. 

 Besides the labial set proper, there are other long bristles, also mostly color- 

 less, in tufts over the eyes, and scattered about the ears ; both lips are thickly 

 fringed with similarly colorless, short, but still stiff, bristly hairs, in addition 



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