DEVELOPMENT. 2038 
are laid before they can hardly be said to have become 
fully formed as eggs. The eggs of Birds are laid when 
there is scarcely a trace within them of the germinal spot; 
while the eggs of Mammals are retained by the parent 
till after the egg-stage is passed.” NRuminants and ter- 
restrial Birds are born with the power of sight and loco- 
motion. Most Carnivores, Rodents, and perching Birds 
come into the world blind and helpless; while the human 
infant is dependent for a much longer time. 
1. Metamorphosis. 
Few animals come forth from the egg in perfect condi- 
tion. The vast majority pass through a great variety of 
forms before reaching maturity. These metamorphoses 
(which are merely periods of growth) are not peculiar to 
Insects, though more apparent in them. Man himself is 
developed on the same general principles as the Butterfly, 
but the transformations are concealed from view. The 
Coral, when hatched, has six pairs of partitions; after- 
ward, the spaces are divided by six more pairs; then 
twelve intermediate pairs are introduced; next, twenty- 
four, and so on. The embryonic Star-fish has a long 
body, with six arms on a side, from one end of which 
the young Star-fish is apparently budded off. Soon the 
twelve-armed body dies, and the young animal is of age. 
Worms are continually growing by the addition of new 
segments. Nearly all Insects undergo complete metamor- 
phosis, 7. ¢., exhibit four distinct stages of existence—ege, 
larva, pupa, and imago. The worm-like larva’ may be 
called a locomotive-egg. It has little resemblance to the 
parent in structure or habits, eating and growing rapidly. 
Then it enters the pupa state, wrapping itself in a cocoon, 
or case, and remaining apparently dead till new organs 
are developed; when it escapes a perfect winged Insect, 
or imago.”* Wings never exist in the larva; and Insects 
