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POPULAR SCIENCE REYIET7. 
tliose islands which /? , not readily admit of being grouped under other geo- 
graphical categories : i.e. besides the Pacific Islands, to which the term is 
usually applied, such isolated spots of land as St. Helena, St. Paul, and 
Amsterdam island, but also including, erroneously it seems to us, sucb 
islands as Formosa, Japan, Sumatra, and Borneo, which the ordinary reader 
would certainly look for under the head of Asia; and, most important of all, 
the addition of a classified index of new species to the section devoted to 
palaeontological contributions. To the working palaeontologist this index 
will be an inestimable boon. It is classified only as far as the great zoolo- 
gical groups generally called classes, and under each of these the species 
are arranged in the alphabetical order of their generic names, so that all the 
difficulty that might easily arise from the adoption of a classification in 
more detail is avoided, and the palaeontological student has merely to run 
down a column or two of names to see whether there is in the volume any 
record of a new fossil in which he may be interested. 
The present volume is considerably larger than its predecessor, and in- 
cludes, with the supplement for the year 1874, no fewer than 2,350 entries 
of papers and separate works published. The labour of preparing all these 
notices, most of which include a brief statement of the general contents or 
bearings of the works referred to, must have been very great, and the thanks 
of all geologists are due to Mr. Whitaker, the editor, and his staff of as- 
sistants, for carrying cut to a successful issue so arduous an undertaking. 
We can only echo Mr. Whitaker’s hope that the number of subscribers will 
increase sufficiently to enable him for many years to continue and even 
extend his valuable labours. 
DIFFERENT FORMS OF FLOWERS.* 
I T is a curious coincidence (though perhaps not without its appropriate- 
ness) that the grandson of Erasmus Darwin should be the great authority 
on what we may venture to call the 11 prohibited degrees of relationship n 
among plants. To the older naturalist it was an easy matter to discourse 
poetically upon the phenomena of the fertilization of plants, then but little 
known except to the professed botanist ; but he might have felt his genius 
trammelled had he known anything of the wonderful series of restrictions 
upon indiscriminate fecundity which the persevering researches of his great 
descendant have brought to light. 
In two numbers of this Review published during the present year we 
have had occasion to notice the appearance of works from Mr. Darwin’s 
hand bearing upon this subject, namely, an original treatise upon “ the 
effects of cross and self-fertilization in the vegetable kingdom,” in which 
the general evidence from which it may be inferred that cross-fertilization 
is to be regarded as a necessary process, even in the case of hermaphrodite 
flowers, is brought forward ; and a second edition of the wonderful book in 
which the cross-fertilization of the orchids is described. We have now before 
us a third volume, the contents of which scarcely yield in interest to those of 
* “ The Different Forms of Flowers on Plants of the Same Species.” By 
Charles Darwin, M. A., F.R.S. 8vo. London : John Murray. 1877. 
