Address to the British Association 199 



in or near their present head-quarters — Madagascar, — then 

 some of the most aberrant forms are those which must have 

 migrated farthest. The character which is perhaps the most 

 peculiar of any which the group presents, is the elongation 

 of two of the ankle-bones, as we find it in the Madagascar 

 genus Gheirogaleus. But this character is more exaggerated 

 in migrants to Africa — the Galagos — and most so of all in 

 the more isolated emigrant, the Tarsier, now found in Celebes 

 and Borneo. 



The sub-family of Slow-Lemurs {Nycticehince) would, on 

 this view, seem to have migrated in opposite directions, as 

 we find the slender Slow-Lemur (Loris) in Madras, Malabar, 

 and Ceylon ; the typical Slow-Lemur {Nycticehus) in South 

 China, Borneo, and Java ; the Potto (Perodicticus) in Sierra 

 Leone, and the Angwantibo (Arctocebus) in Old Calabar. Of 

 these, it is the African forms which have the index-finger most 

 atrophied — a tendency to its atrophy existing in the whole 

 sub-family. 



It would, of course, be very easy to multiply instances of 

 the kind ; but it would be also easy to cite a number of cases 

 which appear to conflict with the view in question. Thus 

 familiar to us as it is, few animals are more peculiar in 

 structure than the common Mole, which gives no present 

 evidence of isolated origin ; and the most aberrant of all Bats, 

 the Vampire (Desmodus), is rather widely distributed in 

 South America. Again, with regard to the Lemur group, the 

 most absolutely exceptional is the Aye- Aye (Cheiromys), 

 which, on the hypothesis supposed, has remained persistently 

 at the head-quarters of the group, i.e. in Madagascar. 



But even if no exception existed to the co-existence 

 now of singularity of form with isolation and remoteness of 

 situation, we could not safely draw any decided conclusion 

 from such facts, because fossil remains show us that forms 

 which have a very limited distribution were either widely 



