150 Transactions. — Zoology. 



colour in the plate is not that rich indigo-blue characteristic 

 of the bird when seen from in front with the light well on it, 

 but a dull greyish-blue, which does not do justice to the bird's 

 beauty. The wings, again, are not uniformly green, but 

 varied, as is correctly represented in the first edition. The 

 long quills are dark-blue, hke the breast, but scarcely so rich 

 in tone; and the major coverts of the primaries are oHve- 

 green, or, rather, bronzy-green, like the back. There is a 

 broad band of the same tint across the base of the wing. 

 Each individual quill has the lower part of the vane blue, its 

 upper part brownish, or, in some hghts, nearly black. The 

 tail-feathers have not brown shafts, nor are they dark-brown 

 below. I am here only calling attention to defects in the 

 drawing, for nothing can be added to Buller's careful descrip- 

 tion beyond the expression of opinion that "purplish-blue" 

 does not seem to me quite the right term. I have called it 

 "indigo-blue," as it appears to me that the colour is a pure 



rich blue. 



An interesting fact in regard to the colour of the bird, and 

 one which must be of the greatest value to the bird itself, is 

 immediately noticeable in examining the skm in different 

 lio-hts. The best effect is obtained when the light and the eye 

 are in the same direction and the front of the bird be looked 

 at. But if we now look at the back of the bird— as it would 

 be seen if it were running away from the pursuer— no bright 

 tint is to be seen. The colour is a dull dirty grey, admirably 

 adapted for concealing the bird as it escapes into the bush or 

 amongst any growth higher than itself and capable of casting 

 a shade. The white under-coverts of the tail form, however, 

 a conspicuous mark in the bird, as in so many of its allies, 

 and though more noticeable when seen from the side in con- 

 trast with the brighter colours of back and wing, yet, from 

 behind, the white is not so noticeable as might be imagined. 

 It is difficult to say what meaning is to be attributed to this 

 white tail. In many cases, like antelopes, rabbits, &c., it is a 

 "recognition mark," as Wallace has called it, enabling mem- 

 bers of the herd to find their fellows at night, or to follow the 

 lead of others in escaping enemies. It usually occurs in 

 animals of gregarious habit, and we should judge therefrom 

 that Notornis is gregarious. It is all the more curious, then, 

 that isolated individuals have been caught and nothing seen 

 of their fellows. But from what enemy does Notornis flee ? 

 What native animal at the present day preys on Notornis ? 

 Probably none. Then, this "recognition mark" must have 

 come down from a time and a place in which there were 

 enemies. This is a matter which at the present time I will 

 not follow up ; but it is evident that it is a matter of some 

 interest and perhaps importance. 



