Allometric growth characterizes probably all living beings. The term means differential growth and refers to developmental patterns of growth which are not uniform, that is, not all parts of the organism develop at the same rate. An example, known to all who look at babies and adults and note the differences therein, is head size. While it is true that an adult head is larger than a baby's head, it is in fact relatively (in relation to the baby) smaller. A late fetus has an enormous head in relation to its body length. Differential growth accounts for the changing proportion of head size. Perhaps an equally obvious instance of allometry is leg length in humans. The fetal and newborn baby have short, chubby, and ineffectual legs. The proportion of leg length to body length is low. About half of the adult height is accounted for by...