MAMMALIA. 315 



life, vary very considerably. In the infant (fig. 80) the hand 

 is by far the most completely developed (in size), next to 

 this the abdomen, then the chest and upper extremities, and, 

 finally, the lower extremities. In the adult (fig. 81), the 

 largest measurement is round the chest and shoulders, but iiT 

 the infant it is round the head ; in the adult the lower extre- 



FIG. 81. IIEAD OP AN ADULT. 



mities weigh one half of the whole body, but in the infant 

 not one quarter. The infantile face has many peculiarities, 

 so also has the face of old age (fig. 82). In the infant 

 the lower part of the face is but little developed, the lower 

 jaw is small, the chin scarcely at all prominent, and the 

 distance from the nose to the chin very short, owing to the 

 absence of the teeth, or (when formed) their smallness. The 

 bones of the nose are scarcely formed, and this organ has 

 therefore no bridge, properly so called; the nostrils are 

 small, the lower part of the forehead small, smooth, and 

 rounded, and the arches of the eyebrows but little promi- 

 nent. The cheek-bones are small, and so are the bony 

 arches which join them to the temples ; the cheeks are fiill 

 of fat, and the angles of the jaws rounded. In middle 

 age the lower part of the forehead becomes more fully 

 developed, the bony edges which support the eyebrows 



