io8 ' MAMMALIA ORDER V.RODENTIA. 



u The pocket-gophers in working their way through the earth in the 

 construction of their tunnels, use the powerful upper incisors as a pick to 

 loosen the ground. At the same time the fore-feet are kept in active opera- 

 tion, both in digging and in pressing the earth back under the body, and the 

 hind-feet are also used in moving it still further backwards. When a suffi- 

 cient quantity has accumulated behind the animal, he immediately turns in 

 the burrow, and by bringing the wrists together under the chin with the 

 palms of the hands held vertically, forces himself along by the hind-feet, 

 pushing the earth out in front. When an opening in the tunnel is reached, 

 the earth is discharged through it, forming a little hillock that resembles in 

 a general way the hills thrown up by moles. In many species there is a 

 naked callosity over the front half of the nose, which must be of great 

 assistance in the construction of the tunnels. When this callosity 

 is largely developed, the nasal bones underneath are highly arched or 

 inflated." 



The same writer then goes on to objei ve that he was much surprised to 

 see a captive example of one of the species run as rapidly backwards as for- 

 wards. " This method of progression was particularly noticeable when the 

 animal was in his own quarters, where he could follow a runway or an accus- 

 tomed route. When carrying food to one of his store-houses he rarely turned 

 round, but usually ran backwards to the place of deposit, returning for more, 

 and repeating the operation again and again, the to-and-fro movement 

 suggesting a shuttle on its track." 



The cheek pouches, which are clothed internally with fur, according to the 

 same author, * ' are used exclusively in carrying food, and not in carting dirt, 

 as often erroneously supposed. They reach back as far as the shoulder, and 

 are so attached that they cannot be completely averted without rupture of 

 their connections." Writing of a tame specimen, Dr. Merriam observes that 

 *' the manner of eating was peculiar and interesting, and showed an ability 

 to use the huge fore-feet and claws in a way previously unsuspected. After 

 satisfying the immediate demands of hunger, it was his practice to fill one or 

 both cheek pouches. His motions were so swift that it was exceedingly diffi- 

 cult to follow them with sufficient exactness to see just how the operation 

 was performed. If a potato was given him, or a piece too large to go into 

 the pouch, he invariably grasped it between the fore-paws, and proceeded to 

 pry off a small piece with the large lower incisors. He would then raise 

 himself slightly on his hind-legs and hold the fragment between his fore- 

 paws while eating, for he usually ate a certain quantity before putting any 

 into the pouches. If small pieces were given him he took them promptly, 

 and passed them quickly into the pouches. Some pieces were thus disposed 

 of at once ; others were just trimmed by biting off projecting angles. As a 

 rule, one pouch was filled at a time, though not always, and the hand of the 

 same side was used to push the food m. The usual course is as follows : A 

 piece of potato, root, or other food is seized between the incisor teeth, and 

 immediately transferred to the fore-paws, which are held in a horizontal 

 position, the tips of the claws curving toward one another. If the food 

 requires reduction in size, the trimming is done while held in this position. 

 The piece is then passed rapidly across the side of the face with a sort of 

 wiping motion which forces it into the open mouth of the pouch. Some- 

 times a single rapid stroke with one hand is sufficient ; at other times both 

 hands are used, particularly if the piece is large. In such cases the long 

 claws of one hand are used to draw down the lower side of the opening, 



