THE OPOSSUM MOUSE. 



457 



into two folds of skin, so that the mother is obliged to find other means of carrying 

 her young from place to place. In the structure of the animal there is an admirable 

 provision for sustaining the pouch and its contents, and preventing it from exerting too 

 painful a " drag " upon the skin and walls of the abdomen. Two supplementary bones, 

 called, from their position in the pouch, the marsupial bones, issue from the pelvis, and 

 are directed forward almost parallel to the spine. On account, however, of the method 

 in which certain muscles wind round the marsupial bones, and taking into consideration 

 the fact that these structures are found in both sexes, Mr. Owen considers that their 

 chief aim is not so much in affording support to the pouch as in compressing the nu- 

 merous glands, so as to aid the feeble young in gaining nourishment. 



We will now leave their general consideration, and proceed to examine some of the 

 principal species which are contained in this wonderful group of animals. 



AT the head of the Macropidae are placed a small but interesting hand of marsupial 

 animals, which are called Phalangistines, on account of the curious manner in which 

 two of the toes belonging to the hinder feet are joined together as far as the " pha- 

 langes." The feet are all formed with great powers of grasp, and their structure is in- 

 tended to fit them for procuring 

 their food among the branches 

 of the trees, on which they pass 

 the greater portion of their ex- 

 istence. 



These creatures fall natu- 

 rally into three subdivisions 

 namely, the Petaurists, or those 

 which are furnished with a para- 

 chute-like expansion of the skin 

 along the flanks, much re- 

 sembling a similar structure in 

 the colugo, or flying lemur, 

 which has been already de- 

 scribed in page 88 ; the Pha- 

 langists, or those which are de- 

 void of the parachute, and are 

 furnished with a long prehensile 

 tail ; and the Koalas, or those 



which are devoid of both para- OPOSSUM MOUSE.- 



chute and tail. According to 

 many excellent authorities, these three subdivisions are, in fact, three genera, which 

 comprise the whole of the Phalangistines, and which render any further separation into 

 genera entirely unnecessary. 



FIRST, and least of the Phalangistines, is the beautiful little animal which is called 

 the OPOSSUM MOUSE in some parts of the country, and the FLYING MOUSE in others. 



This pretty little creature is about the size of our common mouse, and when it is 

 resting upon a branch, with its parachute, or umbrella of skin, drawn close to the body 

 by its own elasticity, it looks very like the common mouse of Europe, and at a little 

 distance might easily be taken for that animal. In total length it rather exceeds six 

 inches, the length of its head and body being about three inches and a half, and that of 

 the tail not quite three inches. On account of its minute size, this animal is also called 

 the PIGMY PETAURIST. 



In the color of the upper portions of the body the Opossum Mouse is of the well- 

 known mouse tint, slightly sprinkled with a reddish hue ; but on the abdomen, and 

 under portions of the skin-parachute, the fur is beautifully white. The line of demar- 

 cation between the hair is very well defined, and there is a narrow stripe of darker 

 brown that marks out the line of juncture. When the animal is at rest, the parachute 



