334 MR. A. R. WALLACE ON THE BIRDS [ Dec. 9, 
lieving such to be the case, I should probably have taken no trouble 
to obtain a collection from thence, had I not been told by many of 
the natives who trade to Sula that a beautiful little bird of the Par- 
rot family was found there and in no other place. In consequence 
of this and other more or less vague information about its productions, 
I arranged with my assistant, Mr. Allen, to go there for two months. 
Owing to bad weather, ill health, and the usual troubles about boats, 
men, and provisions, he obtained but a very small collection, made on 
the southern and eastern islands. Only forty-eight species of birds 
were obtained, yet out of these there were seven new species, which 
appear to be altogether peculiar to this little group of islands; five 
or six others are rare birds of the Moluccas or Celebes, and the re- 
mainder the commoner species from the same countries. 
But although the Sula Islands show a mixture of the forms of 
Celebes and the Moluccas, yet these countries have not contributed 
towards its fauna in anything like an equal proportion. Deducting 
ten species which have a wide range over a large portion of the Ar- 
chipelago, and even beyond it, and dividing the remainder into two 
portions—those that may be supposed to have been derived from 
Celebes on the one hand, and from the Moluccas and islands to the 
east and south of them on the other,—we shall find that the Celebesian 
forms are almost exactly double the rest. Twenty species are iden- 
tical with birds found in Celebes, and five new species are of Cele- 
besian forms ; whereas only eleven species are found also in the Mo- 
luccas, and but two of the new species can be affiliated to Moluccan 
types. Twenty-five of the species of the Sula Islands must there- 
fore have been derived from Celebes, and only thirteen from the 
Moluccas. The accompanying Table (p. 335) shows the species 
distributed according to their derivation. 
It is further interesting to remark that all the Raptores and all 
the Pigeons and Parrots, but one of each group, are Celebesian species 
or forms; while among the Moluccan species are many active but 
weak-flying birds, including five species of Flycatchers, which would 
be most likely to be carried over by strong winds. Further, the 
birds derived from the Moluccas contain three genera which do not 
occur in Celebes. 
From these facts it seems to me clear that the Sula Islands are 
really an outlying portion of Celebes, and must at some former period 
have had a much closer connexion with that great island than at 
present. The Moluccan species must therefore be considered as im- 
migrants, many of them from Bouru, which is only forty miles di- 
stant; and the fact that some of these early Moluccan immigrants 
have already become modified into distinct forms, some of which may 
be classed as species, others as varieties, shows for how long a period 
of time the small and scattered islands of the Moluccas must have 
remained in their present disconnected state. 
The following Table shows the geographical affinities of the birds 
of the Sula Islands :-— 
