ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 215 



Diatoms from Hanover and the Harz.* — A. Peter gives a list of 

 Diatoms from Southern Hanover and the Harz Mountains, with their 

 distribution. C'Omparisons are made between the different localities, 

 and critical repiarks are o:iven. Twenty-eight genera and 173 species 

 and many forms are recorded. 



Changing Diatoms of Devil's Lake, North Dakota.f — C. J, Elmore 

 discusses the phenomenon of the changing diatoms in Devil's Lake, 

 North Dakota. The lake is passing through a rapid transition, having 

 been formerly a fresh- water lake fed by streams. The water is now 

 becoming salt, but the salinity is quite different from that of the sea. 

 The author identified 56 species of diatoms. Of these, 25 are genuine 

 fresh-water species ; 20 are found in fresh or brackish water; 2 in fresh, 

 brackish, or salt-water ; 2 in brackish or salt-water ; and 4: marine only. 

 The importation of the marine species can be explained by the action of 

 migratory birds. The greatest anomaly is presented by the 25 species 

 of fresh-water diatoms, for there is nothing in their appearance to indicate 

 that they have been in any way modified by their change of environ- 

 ment. This fact would tend to confirm what has been observed else- 

 where, namely, that diatoms adapt themselves readily to changes in 

 environment. 



Myxophycese of North America. J — J. E. Tilden publishes a synopsis 

 of the Blue-green algaj. The first part of her work is devoted to an 

 account of the group under the following headings : Collecting Blue- 

 green alga?, structure, reproduction, water-supply alga?, thermal algte, 

 calcareous algse. Descriptions are then given of the families, Chroo- 

 coccacete, Oscillatoriaceai, Nostocacese, Scytonemacese, Stigonemacese, 

 and Eivulariaceae. Then follow keys to the genera and species, with 

 references to the figures on the plates. A glossary and bibliography 

 complete the work. 



Algae of Michigan. § — E. N. Transeau publishes a list of algse 

 collected by himself and others in the ponds, lakes, and streams. The 

 species are for the most part new records for the State. In addition to 

 the records, there are some indications regarding the distribution of the 

 fresh-water alga? that are of interest. The variety and abundance of 

 the Green algas decrease notably as we go northward, while the Blue- 

 green algie form an increasingly conspicuous part. Zygnema cyano- 

 spermum Cleve, previously reported only from Greenland, is recorded. 

 One new species and two new varieties are described. 



Desmid Flora of Dartmoor. || — G. T. Harris has explored five 

 districts of middle and north Dartmoor — Metherall, Gidleigh, Lydford, 

 Haytor, Postbridge— and gives a tabular census of the 391* species and 

 varieties, with their distribution and relative frequency ; also a general 



* Nachr. kgl. Gesell. Wiss. Gottingen, 1913, pp. 1-83. See also Bot. Centralbl., 

 cixxv. (1917) pp. 68-9. 



t Bot. Gaz., Ixv. (1918) pp. 186-90. 



i Trans. Amer. Micr. Soc, xxxvi. (1917) pp. 179-266 (13 pis.). 



§ Ohio Journ. Sci., xvii. (1917) pp. 217-32. 



II Journ. Quekett Micr. Club, xiii. (1917) pp. 247-76 (2 pis.). 



