244 
Review. 
Chapter V. is concerned with the subject of the foliage of 
these plants ; owing to the evidence accruing from mature imprints 
as well as exact details of prefoliation and frond structure, “ the 
picture of Cycadeoidean foliage becomes unexpectedly complete.” 
It is owing to the preceding dense enveloping growth of ramentum, 
that the various foliar organs have been so well preserved. In the 
case of the specimen C. colossalis “there appears to he more or less 
of a hiatus in growth between the series of partially emergent 
fronds and the ramentum areas immediately succeeding them.” 
“ Hence we cannot doubt that in many of these plants growing 
amidst the generalised tropical conditions of the Upper Jurassic 
as far to the north as the Black Hills (44"N), the wilting down of 
old leaves and the growth of new crowns mainly proceeded with 
the seasons.” 
Section III. deals with the reproductive structures, and is, 
perhaps, the most absorbing and interesting part of the whole work. 
It is no exaggeration to say that our author, as is evinced in this 
section, has risen, in the triple labour involved in the collection of 
the material, restoration of the structure, and detailed description 
of the latter, to a high level of merit as a botanical investigator and 
writer. As regards the ovulate cones with which Chapter VI. deals, 
he abundantly confirms and extends the able researches and des¬ 
criptions of Carruthers, Solms-Laubach, and Lignier. Side by side 
with his lucid explanations, we are supplied with such a wealth of 
accompanying text-figures and photographs, as to render the compre¬ 
hension of the complex structures treated of comparatively easy. 
One of the exhilarating features of our author’s new treatment of 
this subject consists in the great variety of types now for the first 
time presented to our view, a variety concerned more especially 
with the relative length and development of the peduncle, and of the 
seed-bearing part of the axis. But by far the most important result 
accruing from the investigation of the new material is that these 
wonderful cones were all, completely or incompletely, bisexual! 
This is shewn by the presence of the “ hypogynous annular shoulder 
indicating the earlier attachment of a dehiscent staminate disk” 
intervening between the highest of the enclosing bracts and the 
lowest seed-bearing pedicel. The following statement of the 
author is also suggestive: “while a bisexual strobilus is primarily 
indicated, the form of fructification is precisely the one capable of 
most varied phases of monoecism and dicecism ”; and “while 
dioecious and monoecious or mixed bisexual forms are suspected to 
