S76 MURIDyE— EPIMYS 



The skull is strongly built, with well-marked supra - orbital 

 ridges, which generally extend back to the outer corners of the 

 inter-parietal ; the front edge of the zygomatic plate is always 

 convex ; the posterior border of the palate is a simple shelf ; 

 the pterygoids are thin plates, and the pterygoid fossae are 

 deep and well defined. The incisors are much deeper than 

 broad, and their wearing surfaces are normal and unnotched. 

 The cheek-teeth (PI. XXVIII., Figs. 8 and 9) are character- 

 ised by the complete suppression of cusps 7 and 3 in upper 

 molars, which have consequently never more than three outer 

 and two inner tubercles. The tubercles show a nearly 

 transverse arrangement, and because of this and the more or 

 less relatively large size of those forming the median row, 

 the teeth, in the higher species, acquire something of a 

 lophodont or laminated character — a feature which .becomes 

 better marked in certain more highly specialised Oriental 

 relatives, e.g. Nesokia. m]- are never longer than the combined 

 length of m^ and ^■, m\ show no tendency to disappear. 



The mammae vary from six to twelve or more ; typically there 

 appear to be three pectoral and three inguinal pairs, and, so far 

 as is known, at least one pectoral pair is present in all species. 



The young, born naked, soon acquire a soft, thick, and mole- 

 like pelage, in which as a rule the dense underfur is grey ; 

 their colour is largely dependent upon this underfur ; the 

 upper parts are therefore greyer than in adults, and the belly is 

 dark grey. The moult appears to take place usually in a gradual 

 and inconspicuous manner, but in some Indian specimens of 

 the rattus group the new fur of the rump is sharply separated 

 from the old coat remaining on the head and shoulders. 



The true rats may be regarded as the most successful of 

 existing terrestrial mammals. Their activity, intelligence, 

 prolificacy, and power of procuring and assimilating a great 

 variety of foods are all of a very high order. The higher 

 species are at home in all climates and under all conceivable 

 conditions, except perhaps extreme cold. They accompany 

 our ships to sea, and swarm in our houses. Although highly 

 palatable, their cautious and cunning habits, their vigorous 

 courage and high powers of defence and offence, enable them 

 to attain a size which would be fatal to the continued existence 



