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described as progressive. On the other hand, an organ 
undergoing degeneration might be regarded as a degraded 
organ, a remnant or a relic of a past perfection and effi 
ciency ; or as an atrophied organ referring to the process 
of wasting away, of which its modification is an illustra 
tion. If such a nomenclature could have been adopted, 
we should always have known exactly what a writer 
meant, supposing that he was careful in the use of his 
terms. 
We have already seen, that Mr. Lydekker says that the 
change of view introduced by the theory of Natural Selec 
tion has given to the word “ rudiment ” a meaning in 
scientific discussion the very opposite of that which ob 
tains in common parlance. Innumerable instances might 
be quoted to show the truth of this assertion :— 
“ Rudimentary organs may be compared with the letters in a word, 
still retained in the spelling, but become useless in the pronuncia 
tion, but which serve as a clue to its derivation.”—(Origin of Species, 
p. 402.) 
“ It appears probable that disuse has been the main agent in 
rendering organs rudimentary. It would at first lead by slow steps 
to the more and more complete reduction of a part, until at last 
it became rudimentary, as in the case of the eyes of animals in 
habiting dark caverns.”—(Origin of Species, p. 400.) 
The term “rudimentary ” is also used to signify what is 
functionally useless, though constitutionally perfect. 
“ An animal may possess various parts in a perfect state, and yet 
they may in one sense be rudimentary, for they are useless.”—(Origin 
of Species, p. 397.) 
. . . “the remarkable rudimentary organs—eyes that see not, 
wings that are never used in flying, muscles that do not contract.”— 
(Haeckel. Essays, p. 2So.) 
Once more the same organ is treated as rudimentary 
from one point of view and non-rudimentary from another. 
FF