REVIEWS 
PALEONTOLOGY. * 
P ROFESSOR NICHOLSON has published so many text-hooks and 
manuals on various subjects of Natural History, that in a very short 
time, if he continues in the same fashion, his works of this kind will make a 
small library of themselves. His latest production is a second edition of his 
Manual of Palceontology , the first issue of which took place just seven years 
J ago, and this has been so thoroughly revised and so greatly augmented that, 
as he himself tells us in his preface, it may be considered practically a new 
book, although of course in the general treatment of the subject the author 
has followed much the same lines that were laid down in his former edition. 
The last section of the first edition, treating of Palaeontology from a his- 
torical or stratigraphical point of view, has been expanded by the author into 
a separate book, having the title of The Ancient Life-History of the Earth, 
in which the subject is developed in much more detail than could be com- 
patible with the plan of the present work, and hence the author has thought 
it best to omit this section altogether. Thus without diminishing the use- 
i fulness of his book, he has been enabled to avail himself of a considerable 
amount of space for the more complete exposition of his primary subject. 
This consists in a regular, systematic treatment of the fossil forms 
hitherto discovered in the strata of the Earth’s crust, and it must be con- 
fessed that Dr. Nicholson has been most successful in carrying it out. Com- 
| mencing with the Sponges, as the lowest types, he proceeds upwards through 
the various classes of the animal kingdom, the fossil remains of animals 
naturally occupying the greater part of the work ; and in all cases the de- 
scriptions of the fossil forms are preceded by a short introductory essay on 
the characters of the different groups as manifested at the present day, a 
most important element in the philosophical conception of the subject, as too 
| many palaeontologists are inclined to forget that in the interpretation of 
fossils they must be guided solely by considerations drawn from existing 
j species. 
■ E; 1 : 
* A Manual of Palceontology for the use of Students, with a General In - 
j troduction on the Principles of Palceontology. By Henry Alleyne Nicholson, 
! M.D., &c. Second edition, 2 vols. 8vo. Edinburgh and London : Black- 
j wood and Sons. 1879. 
