246 NOTES AND COMMENTS [october 



land surface. " There are several ways in which these plants tend to 

 diminish the water-space and to increase the dry land. By their own 

 decay they form vast masses of vegetable soil in shallow waters and on 

 water margins ; by occupying running streams they moderate the flow 

 of the current and give it time to deposit its silt ; by their creeping- 

 rhizomes and spreading roots they fix the bed of a stream and prevent 

 it being scoured and deepened by floods, and again in times of flood 

 they serve as a sieve or strainer, arresting all floating and much 

 suspended solid matter." This is indeed a familiar theme, but the 

 author discusses it with freshness and with appreciation of its dramatic 

 interest. ...'•' Inch by inch, as the result of this accumulation and 

 decay, the land creeps in upon the mere ; more and more solid grows 

 the edge ; the aqueous plants retreat from the now shallow margin, the 

 terrestrial plants advance, finding firmer footing ; the sedges and reeds 

 crowd on their floating neighbours which need space, and cannot endure 

 the shade ; these, too, press forward, and the open water grows less and 

 less ; it is invested on every side, and it is plain that its complete 

 subjugation is now only a matter of time." It would be of interest to 

 procure some actual measurements of the amount and rate of land- 

 winning, and to study in minute detail the elimination which proceeds 

 as the mere is closed up. 



The Progress of a Great Work. 



Eight parts are now available of " Das Tierreich " — the " Systema 

 Naturae "up to date — which is being issued to an ungrateful world by 

 the German Zoological Society through the medium of E. Friedliinder 

 and Son in Berlin. The magnum opus will give a classification and 

 diagnosis of all living animals, and the issue of eight parts in a 

 relatively short period permits us to hope that we shall live to see it 

 completed. The general editor is Professor Franz Eilhard Schulze, and 

 there are many sub -editors. Of the collaborateurs whose names are 

 published the majority are German, but most of the European countries 

 are represented by well-known workers. Britain is represented by 

 Mr. W. E. Hoyle of Manchester, the Hon. L. Eothschild, Drs. 

 Hartert and Jordan of Tring, Mr. A. D. Michael, Mr. W. E. Ogilvie 

 Grant, and Dr. Bowdler Sharpe in London, the Eev. T. E. E. Stebbing 

 in Tunbridge Wells, and Prof. D'Arcy W. Thompson in Dundee. The 

 part before us is by Dr. A. Labbe, and deals with the Sporozoa; it 

 occupies 180 pages, has 196 figures, and costs 8 "80 marks to sub- 

 scribers, and about a third more if purchased singly. The other parts 

 published deal with various families of birds and mites, with a division 

 of copepods, and with scorpions and Pedipalpi. It is not necessary to 

 point out the magnitude of the boon which this great work will confer 

 on systematic zoology, but perhaps it is permissible to urge individual 



