112 THE INFANCY OF ANIMALS 



ornamentation of this kind has perhaps been reached 

 by the nestUngs of the bearded tit (Panurus biarmicus). 

 Herein the inside of the mouth bears four rows of pearly 

 white, conical projections, suggesting the palatal teeth 

 of reptiles, two rows on either side of the cleft of the 

 palate. These tooth-Hke bodies, which are well shown 

 in the accompanying picture, are not of uniform size, 

 and are set against a background of black surrounded 

 by a rich carnelian red, the whole being framed in by 

 the lemon-yellow gape-wattles, which, however, are not 

 very strongly developed. The tongue is black, with a 

 white tip, and a pair of white spurs at its base. 



What purpose can these strange ornaments serve ? 

 So far we can but speculate on this question, but it seems 

 highly probable that they serve as guide-marks to the 

 parents when feeding their young during this most helpless 

 period of existence — ^for it is to be remarked these colours 

 and patterns soon fade. In most of these cases the 

 young are hatched in rather dimly lighted nests, so that 

 any indication guiding the parents to the centre of the 

 mouth would be of immense value, ensuring economy of 

 food, reducing the labour of collecting, and, what is more 

 important, rendering the meals of the hungry youngsters 

 both regular and sufficient. 



These spots, it may be remarked, occur just in those 

 areas where the mouth is most sensitive to touch, so that 

 they serve a double purpose — they form a guide to the 

 parent, and ensure the mechanical closing of the mouth 

 directly the right stimulus, given by the touch of solid 

 food, is administered. It has been objected that such 

 markings occur also in the case of nestlings hatched in 

 open nests, on the ground, amid short grass, so that no 

 such guide being necessary, the spots are useless. 



