450 
EUDIMENTAKY OEGANS. 
Chap. XIII. 
cations not appearing, in the many descendants from 
some one ancient progenitor, at a very early period in 
the life of each, though perhaps caused at the earliest, 
and being inherited at a corresponding not early 
period. Embryology rises greatly in interest, when 
we thus look at the embryo as a picture, more or less 
obscured, of the common parent-form of each great class 
of animals. 
Rudimentary, atrophied, or aborted Organs ,—Organs 
or parts in this strange condition, bearing the stamp of 
inutility, are extremely common throughout nature. For 
instance, rudimentary mammae are very general in the 
males of mammals : I presume that the bastard-wing ” 
in birds may be safely considered as a digit in a rudi¬ 
mentary state: in very many snakes one lobe of the lungs 
is rudimentary; in other snakes there are rudiments 
of the pelvis and hind limbs. Some of the cases of rudi¬ 
mentary organs are extremely curious; for instance, the 
presence of teeth in foetal whales, which when grown 
up have not a tooth in their heads; and the presence of 
teeth, which never cut through the gums, in the upper 
jaws of our unborn calves. It has even been stated on 
good authority that rudiments of teeth can be detected 
in the beaks of certain embryonic birds. Nothing can 
be plainer than that wings are formed for flight, yet in 
how many insects do we see wings so reduced in size as 
to be utterly incapable of flight, and not rarely lying 
under wing-cases, firmly soldered together! 
The meaning of rudimentary organs is often quite 
unmistakeable: for instance there are beetles of the 
same genus (and even of the same species) resembling 
each other most closely in all respects, one of which will 
have full-sized wings, and another mere rudiments of 
membrane; and here it is impossible to doubt, that the 
