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have been added on inheritance in pure lines, and ! twenty-two lectures, and is based, as the preface ; 
on the effects of environment, besides a large 
amount of new matter in the old chapters. A 
considerable part of the added matter refers to 
the more recent developments of Mendelian work ; 
four lectures on this subject are almost entirely 
new, and include discussions of such matters as 
sex-limited inheritance and sex-determination, 
genetic coupling and repulsion, sterility, ete. 
Papers published during 1913 are referred to, but 
although up-to-date, the book is far more than 
a mere compilation, it rather presents the author’s 
view of the subject illustrated by examples chosen 
from the work of many investigators. It is, of 
course, impossible that in so large a book, dealing 
with matters which are still the subject of contro- 
versy, there should not be much with which many 
readers will disagree. But of the book as a whole 
our chief criticism is that it is too long ; although 
one could ill spare the many half-humorous touches 
which reveal the author’s kindly personality and 
enthusiasm, yet 7oo pages of closely printed 
German are more than the majority of us have 
time to read. As a book of reference it should 
be accessible to every student, but it is written to 
be read, rather than referred to. 
(2) The third edition of Plate’s “Selektions- 
prinzip und Probleme der Artbildung” has also 
been reviewed in Nature (October 15, 1908), so 
that in this case also only the changes introduced 
in the fourth edition need be referred to, As men- 
tioned in the preface, the chief alteration is the 
omission of the section on alternative inheritance, 
since this is dealt with in the author’s “Verer- 
bungslehre mit besonderer Beriicksichtigung des 
Menschen ” (reviewed in Nature, May 22, 1913). 
This omission is counterbalanced by a great en- 
largement of the chapter on inheritance of acquired 
characters, so that the total size of the book is | 
increased by more than I50 pages and many 
figures. This enlargement is due, to a consider- 
able extent, to a full account of the experiments 
of Kammerer and others, which have been pub- 
lished since the previous edition was issued. The 
author’s general attitude is illustrated by his state- 
ment in the preface that “de Vries has mis- 
represented the views of Darwin, and that his 
mutations are identical with Darwin’s individual 
variations”; and “dass nur Lamarckismus und ! 
Selektionismus zusammen die Entstehung der 
Anpassungen und der Arten verstindlich machen.” 
The book is very valuable as a summary, but 
appears to us insufficiently critical in the case of 
some of the examples cited. 
(3) Goldschmidt’s “Einfiihrung in die Ver- 
erbungs Wissenschaft’ (second edition) belongs 
to a somewhat different category. 
NO. 2336, VOL. 93] 
subject. 
| pression of haste, 
| impruved if fewer examples were described, and 
| these ireated more fully. 
tribution to the subject. 
tells us, on the author’s. university course on the 
It has the merits and defects of this — 
kind of treatment; that is to say, its title correctly — 
describes it as an introduction to, rather than a 
treatise on, genetics. It is expository rather than 
critical, and in places leaves an unsatisfactory 
sense of not getting to the bottom of the subject. 
It covers a wide range of subjects, is well illus- 
trated, has a useful bibliography, and throughout 
contains much valuable matter. This is especially — 
the case where it deals with the author’s special — 
branch of the subject, the inheritance of secondary — 
sexual characters. In particular, the author’s 
hypothesis of varying “potency” of the factors 
for secondary sexual characters, and of the sex- 
factors themselves, is perhaps the most interest-~ 
| ing section of the book (lecture xviil.).° He con- 
siders that in certain circumstances a zygote 
which contains factors which would normally pro- 
duce one sex may develop into a hermaphrodite, 
or even an individual of the other sex in con- 
sequence of ‘‘ Potenzverschiebung”’ of the sex- 
factors. Lack of space prevents our giving an 
adequate account of the hypothesis, which may 
have important bearing on the theory of sex-deter- 
In places the book conveys the im-— 
and it would perhaps be 
mination. 
(4) Prof. Schmucker’s “ Meaning of Evolution ” 
belongs to quite a different class. It is a popular 
book on the general principles of the evolution 
theory, and makes no claim to be an original con- 
One of its objects is to 
show that there is no necessary inconsistency be- 
tween a belief in organic evolution and religion. 
It is in general pleasantly written, but does not 
differ conspicuously from other books of the same 
type. 
OUR BOOKSHELP. 
A Descriptive Catalogue of the Marine Reptiles 
of the Oxford Clay. Based on the Leeds Collec- 
tion in the British Museum (Natural History). 
Part ii. By Dr. C. W. Andrews. Pp. xxiv+ 
206+xui plates. (London: British Museum 
(Natural History). Longmans, Green and Co., 
rgi3.) Price 25st 
THE scientific value of the remains obtained by 
Messrs. Leeds from the Oxford Clay near Peter- 
borough is exemplified by the groups forming the 
subject of the present, and concluding, volume of 
this excellent and exhaustive catalogue. In order 
to realise this, a visit is almost essential to the 
Natural History Museum, where a mounted skele- 
: ton of the pliosaurian Peloneustes will come as a 
It consists of | revelation to those unacquainted with the state of 
