183


work above quoted (p. 220) cites Dr. Carl Russ to the effect that

the African Aidemosyne canta?is and its very near ally the Indian

A. vialabarica, which do not meet in a wild state, interbreed

indiscriminately in captivity. In view of cases like these, and

of the fact that extreme forms of intergrading species, such as

Corvus corone and C. cornix, and Coracias indica and C. affinis are

postively known to pair up together, I cannot accept the theory

that such intermediate specimens as occur midway in the range

of intergrading forms represent the parent species in its as yet

undifferentiated form, as has been advanced by some naturalists.

For the progenitor of two given species need not have necessarily

been an absolutely intermediate type, though the hybrid may be

so, as has been proved by experimental breeding. For instance,

we may presume that the ancestor of two species the males of

which exhibit decorative colours, would have resembled the

duller females and young of the existing forms ; e.g., the primitive

ancestor of the common Bullfinch f Pyrrhula europcea) no doubt

resembled P. murina of the Azores, and that of the Linnet

( Linota canncibina) the duller coloured Twite fLinota montium ] .

Yet when these two Finches are crossed in captivity, the “ mule”

has a pink breast, a piece of decorative colouration which was

almost certainly absent in the common progenitors of the Bull¬

finch and Linnet genera.


Lastly there is strong reason to suspect that species arise

suddenly as far as colour-variations are concerned. The Red¬

headed form of the beautiful Gouldian finch (Poephilamirabilis ) ,

is an example, and is especially interesting as showing how such

sports may tend to increase, as it has been found by Dr. Butler

to be more attractive to the hen than the less brilliant black¬

headed variety.



ZOO NOTES.



By J. Lewis Bonhote.


VIII.—APRIL.


April 3 2 Yellow-billed Ducks —Anas undulata


S. Africa. Duck Ponds.


I Wedge-tailed Eagle —Aqnila audax


Australia. Eagle Aviary.


X Greater Sulphur-crested Cockatoo —Cacatua galerita


Australia. Parrot House.


,, 51 Marabou Stork —Leptoptilus crumeniferus


Western Africa. Crane House.


,, 64 Spot-billed Ducks —Anaspcecilorhyncha


India. Duck Ponds



