ALGM. 265 



of the German Plankton Expedition, so far as they con- 

 cern the Algae of the open ocean, prefaced by an essay 

 on the general character of such a flora and the conditions 

 of its existence. The expedition has not added very greatlv 

 to the number of pelagic Algae, nor has it introduced any 

 new types. It also failed to find both Coccospheres and 

 Rhabdospheres, and consequently to furnish material for 

 advancing our knowledge of the most puzzling denizens of 

 blue water. Dr. Schiitt, in devoting a few lines to this sub- 

 ject, appears to favour either of the views, that they may 

 belong to the Foraminifera, or that they may be inorganic 

 formations. This is sinning against the light ; but in any 

 case little value need be attached to his opinion on this 

 subject, since his acquaintance with the objects is, like his 

 views, second hand. He records Halosphczra viridis, hitherto 

 known as a surface organism, from "between 1000 and 

 2200 m." — a remarkable find of a green alga in regions of 

 darkness, to which, however, we may presume it was swept 

 by the movements of water currents. The valuable portion 

 of the book consists of the estimates of volume of the con- 

 stituents of the pelagic flora. Though no new broad fact 

 affecting our knowledge of the general distribution of the 

 pelagic Algae emerges from the present employment of this 

 method of estimation, it is plainly a good method, and after 

 more extended use will give increase of knowledge. 



The extensive work of Prof. Schmitz of Greifswald, in 

 preparation for his forthcoming book on the Floridece, has 

 been so eagerly and conscientiously performed, as exhibited 

 in a series of short papers the most recent of which are 

 grouped under (7), that no student can fail to admire it. So 

 far as his system of the Floridecs has been disclosed to us, 

 it is distinguished by the special weight he has attached to 

 very minute characters, and in some minds there is a mis- 

 giving that this weight is of undue gravity, since it appears 

 to exclude characters of greater prominence, but possibly 

 less stability — that, in short, there is some danger of his 

 system tending towards an artificial one. There may be 

 something in such a misgiving, and certainly characters are 

 none the better for being minute, but from intimate know- 



