The islands may thorel'oiv he diNidcd into zoologically distinct groups 

 as follows : 



(I) The Palawan group, consisting ol' I'alawan and the small islands 

 adjacent to it. Balabac, Cagayan 8uhi. and the Cuyos and Calamianes 

 Islands. The l)irds of this group show a very strong Bornean element. 

 The line of demarcation between the i'liilippines, zoiilogically speaking, 

 and the Palawan Islands passes ix'twccn Silmtu and the coast of Borneo 

 and extends thence northward throiigli ilic Sulu Sea east of the Cuyos 

 group and through Mindoro Strait. 



{'i) The central l'liilipi)ines. ccMuprising the Islands nf W-gros, Panay. 

 (iiiimaras, Masbate, and Ticao. Tliey form a wcll-dflincd natural gntiip. 

 although in the case of Masbate and Ticao tbcrc an- indications of 

 immigration from Luzon. 



(3) Mindoro and some of the islands immediately adjacent to it. 

 including Semerara and (loid)tless also ^'lin. 



(4) L\izon, Catanduanes, .Marinduque. and Lnbang. 



(5) Samar, Leyte, and Bohol. 'J'be Lov'k ulu.< on Bohol proves to be 

 Lor'uulus worcesterl and not Loriciilits aincalis, while the presence of 

 UrthotoitiW'< frontalis and Phabotn'roiii brevirostris among birds and of 

 Galeopithecus phiUppinensis and Tarsiiis sprctnim among mammals 

 points unecpiivocally to the closest zoological relationslii]) between IJobol 

 and Leyte. 



(6) Mindanao and the islands immeiliately adjacent to it fonn a group 

 by themselves. 



("t) I*)asilan must be separated from Mindanao on account of tlie fact 

 tbat it lias a number of representative b)rms of Mindanao species and 

 lacks a number of species characteristic of Mindanao. 



(8) Bongao, Tawi Tawi, Lapac, Siasi. and Sulu form a well-marked 

 natural group, to which Sibutu mu.st probably be a<Uled. 



(9) Tablas, Eomblon, and Sibuyan show no evidence of having been 

 connected with any of the neighboring larger islands. They have a 

 nundu'r of peculiar species of birds, and Tablas and lemdilon sJKudd 

 probably be classed together. 



(10) Cebu can not be regarded as one of the central Pbilippine group, 

 but must be classed by itself. 



(II) The Batanes Islamls have a strong Fornu>san element anxuig 

 their birds. It remains to be .«<een whether tbe Babuyanes Islands must 

 l)e grouped with them or must be considered as detached fragments of 

 northern Luzon. 



(12) Siquijor, Cagayancillo. and (*re>ta de (iailo are island.- of recent 

 origin, and their bird fauna' lia\e been dei-ived from stragglers from 

 neighboring islands. 



While the.se several groups are by no means zoillogically equivalent, 

 each has its highly characteristic s|)ecie> and forms a fairly natural 

 division. 



