404 
ISLAND LIFE. 
[part II, 
true lungs, and this peculiar metamorphosis shows that they 
belong to the amphibia rather than to the reptiles. The Csecilias 
are widely but very sparingly distributed through all the tropical 
regions; a fact which may, as we have seen, be taken as an 
indication of the great antiquity of the group, and that it is 
now verging towards extinction. In the Seychelles Islands two 
species have been found, named respectively Ccecilia oxyura 
and C. rostrata. The former also inhabits the Malabar coast of 
India, while the latter has been found in West Africa and also 
South America . 1 This is certainly one of the most remark- 
able cases of the wide and discontinuous distribution of a species 
known ; and when we consider the habits of life of these animals 
and the extreme slowness with which it is likely they can mi- 
grate into new areas, we can hardly arrive at any other conclu- 
sion than that this species once had an almost world-wide range, 
and that in the process of dying out it has been left stranded, as 
it were, in these three remote portions of the globe. The ex- 
treme stability and long persistence of specific form which this 
implies is extraordinary, but not unprecedented, among the lower 
vertebrates. The crocodiles of the Eocene period differ but 
slightly from those of the present day, while a small fresh- water 
turtle from the Miocene deposits of the Siwalik Hills is abso- 
lutely identical with a still living Indian species, Emys tectus. 
The mud-fish of Australia, Ceratodus forsteri is a very ancient 
type, and may well have remained specifically unchanged since 
early Tertiary times. It is not, therefore, incredible that the 
Seychelles Csecilia may be the oldest land vertebrate now living 
on the globe ; dating back to the early part of the Tertiary period, 
when the warm climate of the northern hemisphere in high 
latitudes and the union of the Asiatic and American continents 
allowed of the migration of such types over the whole northern 
hemisphere, from which they subsequently passed into the 
southern hemisphere, maintaining themselves only in certain 
1 Specimens are recorded from West Africa in the Proceedings of the 
Academy of Natural Science, Philadelphia, 1857, p. 72, while specimens in 
the Paris Museum were brought by D’Orbigny from S. America. Dr. 
Wright’s specimens from the Seychelles have, as he informs me, been 
determined to be the same species by Dr. Peters of Berlin. 
