TASTE. 



investigation by examining the beaks of two chicks of 

 the ring paroquet (Psittaeus torquatus^ ALDROVAND), 

 full grown, but which had not been able to break 

 through the egg-shell. In these he observed a regular 

 set of teeth of which he has published the figures. 



Teeth of the Ring Paroquet [chick] (Psittacus tonguatus). a, The upper 

 and lower mandibles, showing: the teeth on their anterior margins. 

 b, c, The same, viewed from beneath, and from above. d, Portion of 

 the beak of the Blue Macaw {Ara araruuna), showing the teth worn, 

 down by use. 



Upon finding teeth thus distinctly perceptible in 

 the chick, the professor was naturally led to examine 

 adult birds. Accordingly, on examining the beak of 

 the blue macaw (Ara ararauna, LESSON), he found 

 a similar arrangement of the horny substance of the 

 beak to the dental organization in the chick of the 

 paroquet, not indeed so rounded into distinct teeth, 

 but little splinter-like pieces standing almost at right 

 angles to the mandibles and closely compacted. In 

 the instance of the paroquet chicks, he could trace 

 nerves and blood-vessels running towards each 

 toothlet; but in the adult macaw, the tube in which 

 these had apparently lain in the embryo chick was 

 filled with a cartilaginous substance. It will be in- 

 teresting to compare his figures of the structure in 

 the macaw with, those we have already given of the 

 chick paroquet. 



