8 4 6 



THE POPULAR SCIENCE MONTHLY. 



Among the many subjects treated of are 

 relations of past faunas ; origination of 

 faunas ; areas of specific, generic, family, 

 and ordinal distribution ; conditions effecting 

 distribution; migrations of animals; dis- 

 persions ; zoological regions accompanied 

 by a colored outline-map ; distribution of 

 marine life ; nature of marine faunas, such 

 as deep-sea, oceanic, pelagic, littoral ; suc- 

 cession of life ; faunas of different geologi- 

 cal periods ; appearance and disappearance 

 of species, reappearance, extinction, and 

 other subjects dealt with from geological 

 evidence. Here the author enters into in- 

 teresting discussions in regard to possible 

 reappearance of species, quoting opinions 

 and statements from various authors, and 

 leaning somewhat as to the possibility of a 

 species evolving again from the parent or 

 parallel stock. In reading these pages, one 

 is more fully convinced than ever that such 

 apparently inexplicable occurences of iden- 

 tical species in beds widely removed verti- 

 cally are mote rationally explained by the 

 assumption of the very great imperfection 

 of the geological record. As an evidence of 

 this, consider the fact that over two hundred 

 thousand species of insects have been de- 

 scribed as living to-day. Now this class of 

 creatures has been in existence since the 

 Devonian, and probably as numerous in 

 species since the Mesozoic as at the present 

 day, and yet the number of fossil insects 

 described from every geological horizon to 

 the present would not exceed in number 

 the species of the smallest order living at 

 present. A species of Lingula, which is 

 found in a few localities on the southern 

 coast of the United States, if fossilized 

 would very closely resemble certain forms 

 in the Silurian. One might scan the Ter- 

 tiary beds in the Southern States without 

 finding a trace of this species, and yet an 

 elevation of the coast-line of North Carolina 

 might show this ancient worm in great num- 

 bers when the deposits below reveal no trace 

 of it. This might appear to a future geolo- 

 gist like a re-evolution of this species, 

 whereas, judging from what we know of the 

 geographical limitations of certain groups, 

 it can only be interpreted as the preserva- 

 tion of colonics under favorable conditions. 

 Globigerina still survives, because the 

 abysses of the deep sea probably remain in 



the same physical conditions as regards tem- 

 perature, pressure, light, etc., as they did in 

 the Cretaceous, and thus we have this crea- 

 ture and other cretaceous forms persisting 

 to the present day. 



We can heartily commend this book as a 

 convenient and compact treatise on a great 

 and voluminous subject. 



Physiological Botany. An Abridgment of 

 the Student's Guide to Structural Mor- 

 phological and Physiological Botany. By 

 PiObert Bentley, F. L. S. Prepared as 

 a sequel to " Descriptive Botany," by 

 Eliza A. Yocmans, author of "First 

 Book of Botany," editor of " Henslow's 

 Botanical Charts." New York : D. Ap- 

 pleton & Co. 1887. Pp. 292. Price, 

 $1.40. 



The author of this work, Dr. Robert 

 Bentley, is an eminent English botanist, 

 who has had more than thirty years of prac- 

 tical experience as a teacher, and whose va- 

 rious text-books hold a first place in his own 

 country. The present treatise is a model of 

 clear, concise, and accurate statement, giv- 

 ing a complete popular view of the minute 

 structures, the functions, and the develop- 

 ment of the various organs of plants. Great 

 pains have been taken by Professor Bent- 

 ley to bring the different subjects treated of 

 down to the present state of science, and 

 much care has evidently been exercised in 

 condensing the numerous details in each de- 

 partment and arranging them in the best 

 manner for the pupil. 



As physiological botany is the same in 

 every part of the globe, and might exist in 

 its fullness if there were only one species 

 of plant in existence, the fact that this work 

 is by an English author has no bearing 

 upon its use in this country. The "De 

 scriptive Botany," with its contained Flora, 

 published two years ago in this series, and 

 to which this is a sequel, covers all that 

 portion of botanical science which has local 

 bearings. In the introduction to that work, 

 after explaining and enforcing the reasons 

 for an early beginning of the study of plants 

 by direct observation, it is recognized that 

 physiological botany may be pursued with 

 profit by ordinary school methods, and the 

 publication of the present manual was ac- 

 cordingly promised ; and it completes the 

 exposition of botanical science in Applctons' 

 series of science textbooks. 



