104 ALLEN'S NATURALIST'S LIBRARY. 



in the interior more to the south. It is curious, remarks 

 M. Grandidier, to find races and species of the same genus so 

 exactly restricted, that one has only to cross a river, not 

 necessarily large, in order to obtain on one bank certain 

 species of Propithecus, whereas those occurring on the opposite 

 bank may be of a very distinct species or race. To what 

 influence in their surroundings can all these variations be 

 ascribed ? One can understand that species inhabiting a 

 wooded and humid country, or living among granitic moun- 

 tains (as P, diadema does), would differ in size and fur from 

 other members of the same genus which live in dry and arid 

 plains (as in the case of P. verreauxi} ; but how can the great 

 variations that occur in members of the same species living 

 a few miles, and perhaps only a few metres, apart, be explained, 

 when the external conditions are almost the same ? 



Habits. The habits of the different species of Sifaka are 

 very similar. They live in companies of six or eight, and are 

 very gentle and inoffensive animals, wearing always a most 

 melancholy expression, and, as a rule, being morose, inactive, 

 and more silent than other Lemurs. They rarely live long in 

 captivity. In their native state they are most alert in the 

 morning and evening, as during the heat of the day they con- 

 ceal themselves amid the foliage of the trees. When asleep or 

 in repose, the head is dropped on the chest and buried between 

 the arms, the tail rolled up on itself and disposed between 

 the hind-legs. The Sifakas live exclusively on vegetable sub- 

 stances leaves, fruits and flowers their diet not being varied, 

 as in the other groups, by small birds, eggs, or insects. Their 

 life is almost entirely arboreal, for which the muscles of their 

 hands and feet, as well as the parachute-like fold of skin 

 between their arms and body, and their peculiarly hook-like 



