270 MAMMALS. 



not a natural one. They are clotted down (.see Map and List in Appendix) at the Cape of Good 

 Hope, in Abyssinia, the Malayan Peninsida, South of Russia, and the Altai Mountains. There 

 they seem to be found in at least two distinct geographical regions, and perhaps animals of two 

 types are confounded under one head. 



Saccomyina,. 



Pouched Rats. (Map 78.) There are two kinds of Rats i^ossessing cheek-pouches ; 

 the Hamsters, or Rats with internal cheek-pouches : and the Gophers, or those with exter- 

 nal cheek-pouches. There are no sufficient characters for separating the former from the rest 

 of the MuRiNi. The internal cheek-pouches are of so little importance that in one of the genera 

 (Hesperomts) a species occurs possessing cheek-pouches (small, to be sure, but still distinct), while 

 all the rest of the genus are without them. In all arrangements, therefore, the Rats possessing 

 internal cheek-pouches have been left along with the others ; but, as already mentioned, the Rats 

 with external cheek-pouches have been raised by some authors to the rank of an independent 

 family. The characters on which the family, thus constituted, is chiefly rested, are the external 

 cheek-pouches and four molar teeth in each lower jaw ; but as the number of molars in each 

 lower jaw of the normal Murini is not constant, but two in some and three in others, there 

 seems no reason why another group with four should not be admitted, if that were the only 

 ground for separation ; and as to the external cheek-pouches, I think I can, in a few words, show 

 that that is not a character of any very great structural value. A short account of what we know 

 of them will prove this. 



The reader no doubt remembers the representation of a queer-looking animal, which he has seen 

 figured in illustrated natural-history books, like a Mole or Rat, bearing a couple of large, vascular, 

 oval, egg-shaped bodies, apfiarently pinned one to each jaw. Figs, la and 16 are copies of part 

 of it. This figure was meant for a portrait of the Geomys bursarius, or " Sand- Rat of Canada," 

 and the imnatural-looking, egg-shaped bodies, are the cbeek-j)ouches, supf)osed to be filled with 

 grain. It was first described and figured by Dr. Shaw ;* and fuller accounts were afterwards supplied 

 by Richardson of the anatomy and habits of another supposed species, G. Douglasii ; f including the 

 mode in which it filled and emptied its cheek-pouches (by pressing them with its fore-paws). 

 Nay, if any one be sceptical, is there not the stufi'ed specimen from which Dr. Shaw described it, 

 and from which his figure, which until lately has been copied by all subsequent authors, was taken ? 

 It was in Mr. Bullock's Museum, which afterwards passed into the hands of Temminck, and no 

 doubt it is still to be seen in the Leyden Museum. There can surelj^ be no mistake here. But 5-et, 

 is it not rather curious that no one has ever seen another specimen like this, — that even Sir John 

 Richardson never saw it, — that, inhabiting such a well-peopled country as Canada, no one has 

 ever got a peep at it ? Still, there is the specimen itself, challenging contradiction. But when 

 modern science begins to put the subject to the question, we learn that no such /kshs )iafiirw ever 

 existed. It turns out to be an error, originating in the whim of an Indian. J It appears that, in 

 1798, one of this species was jiresented bj^ a Canadian Indian to the lady of Governor Prescott. 

 Its pouches had been inverted, filled, and greatly distended with earth: and from this trivial 

 circumstance an error originated, which has been perpetuated even to the present day. 



Even after the true nature of the animal and its cheek-pouches was ascertained. Sir John 



* " Linnean Transactions," vol. V. ]). 237. J AnDDBON and Bachman, "North American Qua- 



t Richardson, "Faun. Bor. Amer." i. 203. 1829. dnipeJs," i. 3.32. 1849. 



