162 ON SUBFOSSIL PEIMATES FEOM MADAGASCAE. 



2. There is strong presumptive evidence that at the time of their isolation in 

 Madagascar by the severance of that island from the mainland the ancestors of the 

 Indrisidse had already acquired most of the features generally regarded as characteristic 

 of the true Monkeys. 



3. During the subsequent history of the Indrisine group specialisation has taken 

 place in various directions and to very varying degrees. Among the different genera 

 enumerated above, Arclmolemur, Hadropithecus, and Mesopropithecus have retained on 

 the whole the greatest number of pithecoid characters. 



4. Even some of the least specialised forms have undergone retrogressive changes as 

 compared with the ancestral Tertiary stock from which they, in common with the 

 extant Indrisinse, are derived. This is notably true as regards the condition of the 

 frontal region of the brain. 



5. A comparison of the least specialised members of this Indrisine group of Primates 

 with the various families of Monkeys shows relationships with both the Old and JMew 

 World forms, but in several characters reveals closer affinities with the latter than with 

 the former. 



6. A comparison of the Malagasy Lemurinse, recent and subfossil, with the various 

 members of the Indrisine group supports the belief that among certain of these 

 Lemurine genera specialisation has proceeded even further than in the case of the 

 recent Indrisinte. This specialisation has in general proceeded on similar lines in 

 the two groups, though the deviations from the primitive dental formula are less 

 pronounced among the Lemurine than among the Indrisine genera. 



7. The members of the family of the Lemuridse outside of Madagascar are found in 

 scattered genera over a wide area in the Old AVorld and bear the marks of a decadent 

 group, All are nocturnal, and many are curiously specialised. 



8. A comparison of the various genera of Lemuridse with one another and with the 

 New World Monkeys leads to a strong presumption that the different members of 

 this family are all (with the possible exception of Tarsius) survivals of the Primate 

 stock formerly inhabiting the ancient Southern land-mass which includes South 

 America, Madagascar, and a part at least of South Africa and India. They are thus 

 allied to the Malagasy Indrisidai as well as to the Nyctipithecinse and otiier South- 

 American genera, and, more remotely, to the Old World Monkeys. 



9. The terms Lemur and Lemitroid are misleading if they are mtended to imply any 

 close connexion between the recent Lemuridge or Indrisidne and such ancient Northern 

 forms as Adapis and Necrolemur. 



10. In view of the recent additions to our knowledge of the Lemurs and of their 

 close relations to the Apes, it seems no longer necessary, or indeed possible, to separate 

 the Primates into the two sub-orders of Lemuroidea and Anthropoidea. 



