Bibliographical Notices. 73 
of the application of the operations of slicing and polishing. While 
the plants preserved by incrustation display such characters as the 
shape of the leaf and venation excellently, the organic structure 
has practically disappeared, those petrified, on the other hand, 
showing their minute anatomy to a surprising degree. The details 
of cell-structure can be made out with considerable certainty, and 
by painstaking collation of many specimens the entire histology may 
be determined. 
Dr. Scott’s plan is to go methodically through the alliances as 
follows, describing any special structure which may be found in 
them :—Beginning with the Kquisetales, once so grandly developed 
in the Carboniferous period, though now only represented in the 
living series by one genus, then taking up the Sphenophyllales, 
representative of a type of vegetation which has wholly vanished, 
passing to the Lycopodiales, familiar to recent botanists in the 
genera Lycopodium and Selaginella, which are of humble dimensions 
when compared with their ancestral forms, and then the ferns. 
which are better represented in the present day than in the fore- 
going groups. Next in order we have the Cycadofilices, that 
curiously intermediate group between the Ferns and Cycads, which 
is only known in a fossil state, coming lastly to the Mesozoic 
Gymnosperms. 
The object of the author is to compare the structure found in these 
fossil forms with similar structure found in recent plants. Quoting 
with approval Solms-Laubach’s phrase that our object in studying 
the fessil forms is ‘‘ the completion of the natural system,” Dr. Scott 
is careful not to bring up any very doubtful specimens, but te keep 
attention fixed on those specimens which can throw light on the 
problems presented by these fragmentary remains. It would be 
impossible, we think, to read this volume with care and fail to gain 
a very good idea of the organization and the relations of these 
plants, not only to one another, but also to the existing vegetation. 
There is one special difficulty which besets the paleobotanist, and 
that is that fossil genera and species have been founded upon entirely 
ditferent considerations from those which govern the naming of 
recent plants, and this, too, from the very nature of things, as a 
moment’s reflection will show. Owing to the state in which these 
fossils occur, the root, the stem, and the fruit of the same plant 
have sometimes received generic rank only to be reduced as the 
result of examination of a large series or from some lucky accident 
showing the organic connexion of one of these structures to another. 
It is not surprising, therefore, that palaobotany teems with so-called 
genera and species which the systematist of recent plants would 
regard as hopelessiy bad, and that much of the work and much of 
the interest of the present-day paleontologist is deyoted to deter- 
mining the relations of these separated parts. 
The numerous drawings, reproduced by various processes, succeed 
in showing the points desired, mainly in consequence of the care 
spent in selecting the given specimen to bring out the special 
Ann. & Mag. N. Hist. Ser. 7. Vol. viii. 6 
