BOTANICAL EVOLUTION. 369 
_ the embryos of many whales have teeth in their jaws which never 
come into use at all. Many of the higher animals possess rudi- 
mentary muscles. There are, for example, muscles in the ears of 
most of the higher mammalia, for the purpose of moving them freely 
about. We are familiar with them in dogs and rabbits, which prick 
up their ears at any unfamiliar sound, yet we have breeds of both of 
these, in which, by the influence of long domestication, the habit of 
pricking up the ears has been wholly or partially lost, though the 
muscles are still in existence. How many of ourselves can move our 
great toes freely like our thumbs? The muscles exist for moving 
them, but they have become useless, from the habit of continually 
enclosing the feet ina shoe. But most Hindoos, Chinese, and other 
people who go habitually barefoot, use the great toes freely. Rudi- 
mentary eyes are common in many animals which pass their lives in 
the dark, and oecur in nearly every class. The last examples I shall 
cite from the animal kingdom are even more familiar to us than these. 
The Ostrich, Cassowary, Kakapo, and other birds have wings which 
are useless for flight, while the Apteryx (like the extinct Moa) is 
said to be a wingless bird, the wings being so much reduced in size as 
to be externally invisible. Besides all these examples, numerous 
others are to be found throughout the animal kingdom, and are 
referred to in the works of Varwin, Wallace, Haeckel, and others. 
In the Vegetable Kingdom rudimentary organs are equally 
common, and it has often struck me as a singular fact, that no text- 
book on Botany with which I am familiar makes any special reference 
to them. They are familiar enough to all botanists, and are referred 
to in the works of the authors named, as well as in much of the 
recent scientific periodical literature. A few practical examples may 
be of interest to you. Among all the simpler flowers uniformity of 
number of parts or floral symmetry appears to be the usual thing. 
Thus most Sedums and closcly-allied plants have 3-5 sepals, 3-5 petals, 
3-5 stamens, and 3-5 carpels; always a uniform number. Puchsia 
and its allies have 4 sepals, 4 petals, (4 or) 8 stamens, and 4 carpels. 
Now let us take an Antirrhinum, one of the great order Scrophularinee. 
Here we have 5 sepals, 5 united petals, 4 stamens, and 2 carpels. 
It is very rarely the case that the flower ever shows a fifth stamen. 
But here we have one of its allies—Pentstemon—so called from its 
fifth stamen. This is a flower which is evidently not so much 
modified from the primal type as Antirrhinuwm, and is much more 
regular in form than the latter. It has four fully developed stamens, 
and alongside of them a fifth imperfect one, the purpose of which I 
do not know, but whose presence can only be explained on the 
supposition that the ancestral form of Pentstemon was a plant with 
five fully developed stamens. Why one of them is functionless now 
is a question not so easily answered, because the intermediate stages 
and conditions are not known. 
But it is not always the case that the mature plant alone shows 
rudimentary organs. They are, as I have already said, common in 
embryonal stages, and sometimes such embryonal rudiments dis- 
appear before the individual reaches maturity. Perhaps I can best 
illustrate this fact by reference again to the animal kingdom. If we 
examine the skeleton of a fish we find three or four arched bones lying 
behind one another on each side of the head and supporting the gills. 
These are termed the gill-arches. Now if we can get the embryonal 
