1898] SOME NEW BOOKS 275 
there is no absolute certainty that any of these so-called palaeozoic 
Equiseta are identical with the recent genus, he probably takes the 
right course. Among those described are Hguwisetites Hemingwayt, 
Kidston sp. ; Lquisetites spatulatus, Zeiller; EL. columnaris, Brongt.; and 
E. lateralis, Phill. The consideration of Phyllotheca and Schizoneuwra 
lead us up to the Calamites—which is one of the most important 
groups—(for it cannot be considered a genus in any true sense of the 
term)—of palaeozoic times. 
The study of the Calamites is introduced by a historical sketch, 
and this is succeeded by a description of the anatomy of the stems, 
leaves, roots, and cones, each of which is illustrated by good figures. 
This class he treats with great skill and shows a complete mastery 
of a very difficult subject. He recognises three types of Calamite 
stems as determined from internal structure :— 
Arthropitys, which is the type commonly met with in the Lanca- 
shire and Yorkshire Coal Fields. 
Arthrodendron, which is very rarely met with in Britain. 
Calamodendron, which hitherto has not been recorded from Britain. 
The structure of the leaves is next given, after which follows a 
description of the Calamitie genera that are founded on impressions. 
These are :—Calamocladus (Asterophyllites), of which Calamocladus 
equisetriformis is fully described as a typical form. This is succeeded 
by a description of Annularia, A. stellata and A. sphenophylloides 
being given in full detail. The roots of Calamites are next dealt. 
with, and with them is now associated the Astromyelon of Williamson. 
Three types of Calamitic cones are described. These are Cala- 
mostachys (with which is united Stachannularia); Palacostachya and 
Macrostachya. Huttonia is also referred to, but with the exception of 
the first two genera, little is known of their internal structure, with- 
out which their true position cannot be satisfactorily determined. 
Much still requires to be done in the elucidation of Calamitic cones 
and great care must be exercised in forming opinions as to their 
affinities. 
The impressions and casts of stems are now considered and are 
classed under the three sub-genera of Weiss :—Calamitina, Stylo- 
calamites aud Hucalanutes. The study of Calamite stems presents 
considerable difficulty. Many specimens which have been regarded 
as stems are certainly only the casts of the pith cavity, but others, 
such as many Calamitina show the outer surface of the stem. These 
three sub-genera are distinguished by the manner in which the branches 
were borne on the stems—a system of classification which can only be 
regarded as provisional. In very few cases can the foliage and cones 
be associated with their parent stem. 
Archaecalamites, from the Lower Carboniferous and Devonian, forms 
another group, which is closely related in some of its characters to 
Caulamites, but is clearly separated from that genus by several 
important differences in the stem and cones. 
» Chapter xi., which concludes the volume, is devoted to the 
Sphenophyllales. 
As in the previous groups the structure of the stem of Sphenophyl- 
lum is first described. Owing to the numerous specimens of Spheno- 
phyllum which have been discovered showing fine structure, the develop- 
