88 cuscus. 



males ; in anotlier , Cuscus orientalis , have the individuals 

 a dark line on the middle of the back and are the males 

 larger than the females , meanwhile the other species have 

 no spots or baud on the back. 



So the species may shortly be characterized as follows: 



Ears naked internally, 



1 . back with a dark band ; males larger than females : 

 Cuscus orientalis. 



2. no differences in color or size between males and fe- 

 males : Cuscus celehensis. 



Ears clothed internally, 



3. males spotted, smaller than females: Cuscus macu- 

 latus. 



4. no difference in color or size between males and fe- 

 males : Cuscus ursinus. 



The form of the skull permits to distinguish two types, 

 the one by a convexe, the other by a concave forehead. 

 Cuscus maculatus is the only representant of the first type, 

 having a very swollen forehead; the three other species 

 belong to the second type , although in different degrees , 

 viz: the concavity of the forehead is the deepest in Cus- 

 cus orientalis^ meanwhile in Cuscus celehensis it remembers 

 the state of a not fullgrown Cuscus orientalis ; this con- 

 cavity is the less deep in Cuscus ursinus and here the fo- 

 remost parts of the forehead form swollen cushions. In 

 very young specimens already the specific form of the fo- 

 rehead is pronounced, the only differences between young 

 and adult being that in young ones the concavity or con- 

 vexity is less developed and that the crest along the middle 

 of the occiput in fullgrown individuals is in the younger 

 ones represented by two crests : these two crests arise in 

 very young specimens from the sides of the occiput , in 

 growing they approach one another, come together and 

 finally unite into a single elevate crest , which ends at the 

 beginning of the concavity or convexity on the forehead. 

 The named crest is only well developed in perfectly adult 

 specimens, some time after the whole development of the 



Notes from the Leyden Museum, Vol. VII. 



