98 THE JOURNAL OF BOTANY 



plemented with an abundance of excellent illustrations, usually 

 photographs or reproductions of the original figures. 



The original plan of giving separate generic, and sometimes 

 even specific, names to diii'erent parts of the same plant when 

 found as separate fossils is adopted, but reference is given to the 

 other parts when these are known. It is evident that much 

 remains to be done in the direction of linking up isolated frag- 

 ments of stems, leaves, cones, &c., into complete plants. 



When one looks at a book like the present volume, the 

 richness and variety of even a small part of the flora of the 

 ancient Carboniferous Period strikes one very forcibly. It is 

 greatly to be regretted, however, that the author found himself 

 unable to include in his work an account of the petrified speci- 

 mens showing the structure of the plants whose external form is 

 exhaustively dealt with. It is true that some references are given 

 to the literature of this subject, but many more are desirable. 



A more serious drawback is that the book does not contain 

 more critical work. One can easily realize the enormous diffi- 

 culties in the way of a really critical account, as the author points 

 out, but it would have added greatly to the value of the work if 

 such a thing had been possible. 



Dr. Jongmans knows how to make a book. The various 

 sections are clearly arranged, and a good bibliography and index 

 are provided. One can only marvel at his energy and patience in 

 undertaking a work of such great magnitude, and if the other 

 parts are as good as the present appears to be, he will earn the 

 gratitude of many generations of palaeobotanists. 



H. H. T. 



Das Phytoplankton des Silsstvassei's mit hesonderer Berilcksichti- 

 gung des Vienualdstdttersees. By Dr. Hans Bachmann. 

 Pp. 213. 15 plates. Jena : Gustav Fischer. 1911. Price 

 5 Marks. 



This volume is an attempted summary of our present know- 

 ledge of freshwater phytoplankton, with a passing reference to 

 that which occurs in the Lake of Lucerne. The greater part of 

 the work (about 170 pages) is devoted to a general systematic and 

 biological account of the flagellate and algal constituents of the 

 plankton. Some of these groups, such as the Flagellata, Peri- 

 dinecB, and Myxophycecd, are treated very well, the systematic 

 account being based upon the recent w^ork of Lemmermann. 



Ceratiwn hirwidinella receives a more comprehensive treat- 

 ment than has yet been accorded to it, but even this detailed 

 account omits all mention of that peculiar form wdth the deflexed 

 antapical horn which, so far as is known, occurs only in the lakes 

 of the Outer Hebrides and the West of Ireland. 



The treatment of the Diatoms is, on the whole, good, but the 

 complete omission of the genus Surirella is a serious defect, when 

 one considers the great abundance of species of this genus in the 

 lakes of the British area, and in the large African lakes. 



