128 



ZOOLOGICAL GARDENS. 



dependent only upon a more advanced age and a finer 

 state of plumage. The brilliancy and depth of the 

 colouring vary considerably in all the individuals that 

 we have seen; the curvature of the bill and claws 

 seems to go on increasing with the growth of the bird ; 

 and the tooth of the upper jaw, with its corresponding 

 notch in the lower, may possibly undergo a gradual 

 obhteration from the effects of long continued attrition. 

 This beautiful species appears to form the passage 

 between the true Maccaws, in which the whole of the 

 cheeks is bare of the common plumage, and the Per- 

 ruche-Aras of Le Vaillant, the genus Psittacara of 

 Mr. Vigors, in which the cheeks are entirely feathered, 

 with the exception of a circumscribed space encirchng 

 the eyes. In the Hyacinthine Maccaw the cheeks are 

 only partially feathered, naked spaces being left round 

 each of the eyes, and also at the junction of the upper 

 and lower mandibles, the latter passing round beneath 

 the chin. The uniform colour of the whole bird is a 

 hyacinthine blue, of greater or less intensity in different 

 individuals, and deeper upon the quill-feathers of the 

 wings and tail. The naked spaces round the orbits 

 and at the base of the bill are of a brilliant yellow ; and 

 the bill, legs, and claws are nearly jet black. 



