2 [ 
REVIEWS AND EXCHANGES. 
The Cambridge Natural His- 
tory, Vol. I. Macmillan 
and Co. Price 17s. net. 
When we see the excellent 
character of the work we feel 
we must refrain from grum- 
bling at the slowness with 
which this standard work 
is making its appearance. 
Though first in systematic 
order, the present volume is 
the ninth in order of appear- 
ance, so that with one more, 
that on Spiders and Crusta- 
cea, the work as planned will 
be complete. The restriction 
of authorship to workers con 
nected with the University 
of Cambridge cannot be said 
to be felt when it permits of 
the co-operation of four such 
specialists as the writers of 
this volume. Professor Mar- 
cus Hartog, of Cork, treats 
of the Protozoa in the first 
162 pages of the volume, and 
his two preliminary chapters 
are of the very deepest in- 
terest to the general biolo- 
gist. Though he does not 
accept Professor Ray Lan- 
kester’s classification in its 
entirety, we note that he 
includes the Myxomycetes, 
while Eozoon is dismissed 
in a brief foot-note. Miss 
Sollas, of Newnham, treats 
of the Sponges or “ Pori- 
fera ” in about 80 pages, 
giving special attention to 
British and to fossil forms. 
A summary in a single page 
of our knowledge of the 
formation of flint is a master- 
piece of lucid condensation. 
Professor Hickson, of Man- 
chester, deals with the Coe- 
lenterata and Ctenophora in 
180 pages — none too many 
for the complexily of the sub- 
ject — and it falls to his lot to 
summarise the evidence as 
to the origin of coral-reefs. 
Lastly, Professor MacBride, 
of Montreal, has assigned 
to him the Echinodermata, 
which occupy nearly 200 
pages. Our common star- 
fish, Asterias rubens, is taken 
as a type and described at 
