224 MR. A. H. EVERETT ON THE ZOO-GEOGRAPHICAL [Apr. 16, 



Borneo, are all identical with or allied to species inhabiting the latter 

 island or other parts of Indo-Malaya proper. Not one of the few 

 mammals which are peculiar to the Philippines is known to occur in 

 the Palawan group. On the other hand the genera Hystrix, Manis, 

 and Mydaus, which are such as require a continuous land-connexion 

 to enable them to migrate from one area into another, and which are 

 all very abundantly represented in Northern Borneo, do occur in 

 Palawan, while none of them have been recorded as existing in the 

 Pliilippines. So that a study of the relationships of the mammals 

 of the Palawan group seems to show that this portion of the fauna 

 was derived from Borneo and western Indo-Malaya and not from 

 the Philippines ; and not only so, but that continuous connexion by 

 land with Borneo must have existed so as to enable some of the 

 genera which we find in Palawan to have reached that island. It 

 may be argued that bad such continuity of land-surface existed within 

 the lifetime of the present fauna, the mammals of Palawan could 

 not fail to be far more numerous than is known to be the case. But 

 the actual junction may have been of too brief duration to allow of 

 the migration of a large number of species ; or, as is far more 

 probable, the mammals were at one time sufficiently numerous, and 

 they have since been almost extinguished by a general submergence 

 of the Palawan group. There is reason to believe that the Island 

 of Borneo has undergone in comparatively recent times a submer- 

 gence to a depth of probably not less than 1000 feet, from which 

 it is now recovering ; and since Palawan appears to be partaking in 

 the present elevatory movement, it is reasonable to conjecture that 

 it partook also in a less or greater degree of the preceding subsidence, 

 in which case the group must have been reduced to a chain of steep 

 islets affording no scope for the continued existence of a varied 

 mammalian fauna. 



Passing now to the birds, we find that the total number of species 

 authentically recorded from the Palawau group amounts to 161 \ 

 which may be tabulated as follows. 



Table I. — Showing the Palawan Species which are common to 

 Borneo or other parts of western Indo-Malaya and to the 

 Phihpjdnes, together with the Species which are of wide general 

 distribution or are migrants from Continental Asia. 



1. Phylloscopus borealis 



2. Acrocepbalus orientalis. 



3. Monticola solitaria. 



4. Cisticola cisticola. 



5. Motacilla flava. 



6. Anthus maeulatus. 



7. gustavi. 



8. Pericrocotus cinereus. 



9. Lalage terat. 



10. Hemicbelidon sibirica. 



11. ilusicapa griseisticta. 



12. Hypotbj-mis occipitabs. 



13. Cubcicapa cevlouensis. 



14. Hirimdo gutluralis. 



15. javanica. 



16. Sturuia violacea. 



17. Artamus leucorbynchus. 



18. Cbsetura gigantea. 



19. Collocalia fucipbaga. 



20. Eurystonius orieutaUs. 



1 



I exclude Parus eleyans, because tbe accuracy of tbe Palawan locality is 

 very doubtful, and Tumix raynaldi, which Mr. Ogilvie-Grant assures me is 

 identical wth T, nigrcscens. 



