10 
all and passed into a kind of vegetative existence—that might be 
justifiably regarded as degradation. If it commenced existence 
with the special and peculiar endowments of a vertebrated animal, 
and ended in being a mere animated bag of seawater, it would be 
a degraded animal. If it emerged from the egg a freely moving 
creature, swimming hither and thither, and earning its own living, 
and then finished up by burrowing into the tissues of a higher animal 
and feeding on them, it would have degenerated. In fact, when- 
ever an animal loses its higher endowments, parting with specially 
organised limbs or senses, and so seems to have fallen, not merely 
as an individual in a class, but to have actually sunk into a lower 
class—there cannot be much question about it. The frog com- 
mences life as a fish, but developes into something higher than 
that. How should we regard it ifit began as a frog, and ended as 
a fish? Other creatures start very similarly with a tadpole stage, 
but end on a far lower step of the ladder of life. Again, the rats, the 
lizards, fishes, and insects in caves, possessing but mere rudiments 
of eyes, or none at all, are undoubtedly the descendants of rats, 
lizards, fishes, and insects, which possessed fully developed eyes ; 
surely they illustrate degeneration. And this degeneration you will 
notice is sometimes, as with these cave animals, a degeneration of 
the whole species or even genus, and extends through the whole 
career of the individual; in other instances which, I shall first 
illustrate, the gradual descent is traceable in the life of each indi- 
vidual. 
We will take as our first example an animal that occupies a very 
prominent place in all works on development, common on some 
shores, but slighted and passed over by ordinary persons as a thing 
of no beauty, and to which no interest could be attached. I mean 
the Ascidians, a tribe of tunicate Molluscs, possessing characters at 
one period of their life, so peculiar, that some biologists claim them 
for the vertebrate kingdom. In the Darwinian Theory they are 
most important, since the author himself tells us we are justified 
in believing that man is descended from a tadpole-like form closely 
resembling that of our present Ascidians. 
In outward appearance the Ascidian or Sea Squirt is a rough 
leathery bag, like a two necked bottle, found fixed on rocks at low 
water mark. We naturally look upon it as a ‘‘low”’ form of life 
because it is a fixture, and seems to have no relations with the 
outer world beyond the satisfying of its hunger with what may 
chance to flow into its mouth. Yet we are told by naturalists, that 
it alone, amongst all invertebrate creatures, possesses in early life 
the four marks which characterize especially the members of the 
vertebrate kingdom, whilst the action of its heart in propelling the 
blood alternately to the body and to the aerating apparatus, is 
