282 MYOXID/E. 



The situation of the genus Myoocus in the natural 

 arrangement of the Rodenlia is one of some interest, as 

 occupying a position between the Sciuridce, or Squirrels, 

 and the Murida, or true Mice. We do not deem it 

 desirable, in a work like this, to enter at length into 

 the somewhat ample system of classification at present 

 made use of in this great order, but at the same time we 

 are anxious to warn our readers against an opinion on 

 the subject of classification, which we think is much too 

 commonly entertained. We allude to the frequent belief 

 that one animal, or group of animals, often forms a direct 

 link or passage between two other groups ; and the little 

 animal which we have now under consideration has been 

 supposed to constitute one of these links. It does, indeed, 

 connect the Squirrels with the Mice, but it does so only 

 by holding an intermediate position, and not by forming 

 an even gradation from the one to the other ; for the 

 Dormouse, which, partaking of climbing characters on the 

 one hand, has not these peculiarities developed in the 

 same manner as in the Squirrels, but rather to enable it 

 to creep amongst underwood than to climb trees; and on 

 the other hand, although obviously having a certain rela- 

 tionship with the true Mice, it differs, nevertheless, in some 

 important respects. It is a matter of frequent occurrence 

 in intermediate groups, to find that they possess impor- 

 tant characteristics which are quite peculiar to them. 

 Thus, while the number of molar teeth in Mus is three 

 in each jaw, in Sciurus five, and in Myoxus the interme- 

 diate number, yet in the structure of the teeth themselves, 

 the latter differs very materially from both the others, 

 and, indeed, from other Rodentia. This, with some other 

 peculiarities, has induced us, with other zoologists, to 

 recognize as a family the group to which the Dormouse 

 belongs, under the name of Myoxida, coming after the 



