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 Hystrizx, 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 
Philippines. 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 Palawan group amounts to 161', 
which may be tabulated as follows. 
Taste I.—Showing the Palawan Species which are common to 
Borneo or other parts of western Indo-Malaya and to the 
Philippines, together with the Species which are of wide general 
distribution or are migrants from Continental Asia. 
1. Phylloscopus borealis 11. Musicapa griseisticta. 
2. Acrocephalus orientalis. 12. Hypothymis occipitalis, 
3. Monticola solitaria. 13. Culicicapa ceylonensis. 
4. Cisticola cisticola. 14. Hirundo gutturalis. 
5. Motacilla flava. 15. javanica. 
6. Anthus maculatus. 16. Sturnia violacea. 
7. — gustavi. 17. Artamus leucorhynchus. 
8. Pericrocotus cinereus. 18. Cheetura gigantea. 
9. Lalage terat. 19. Collocalia fuciphaga. 
10. Hemichelidon sibirica. 20, Eurystomus orientalis. 
1 J exclude Parus elegans, because the accuracy of the Palawan locality is 
very doubtful, and Turnix raynaldi, which Mr. Ogilvie-Grant assures me is 
identical with 7. nigrescens. 
