610 SUMMARY OF CURKENT RESEARCHES RELATING TO 



Confervoidese (Enter omorpha, OEdogonium, Ghsetophora, Clado2')hora, 

 Vaucheria). In September occurs another maximum of Diatoms, and, 

 under favourable conditions, also of certain Chlorophyceae {Spirogyra, 

 Mougeotia, Conferva, Ulothrix). At the end of October, or at the 

 latest in November, begins the final retrogression of all classes of algas. 

 As regards the flora of the " Danish Creek " (Danische Wiek), Chloro- 

 phyceae and Rhodophycea3 constitute the largest proportion ; Schizo- 

 phycefe and Ph^ophycese are very much fewer. The maximum occurs 

 from June to September. At no time, however, is there an entire lack 

 of algse. The Characese form a typical coast flora, which is explained 

 by the low salinity. The Rhodophycese grow luxuriantly. The Phyto- 

 plankton is represented by Schizophycese (6), Silicoflagellatse (1), 

 PeridiniefB (2), Diatoms (74), and Chlorophyceae (4). The quantitative . 

 results are set forth in tabular form. The Diatoms attain their 

 maximum in April, the principal genera being Chsetoceras, Diatoma, 

 Fragilaria, Synedra, Cocconeis, Rhoicosphenia, Navicula, Epithemia, 

 Nitzschia. Only in April are found Sceletonema and the Silicoflagellate 

 Ebria. Scenedesmus is especially abundant in April. Schizophyceae 

 and Chlorophycese appear first in July and reach their maximum in 

 September and October. Anahaena has its maximum in August. This 

 paper shows, by comparison with the work of Abshagen on the Danische 

 Wiek some years ago, that both qualitatively and quantitatively the 

 composition of the plankton has altered considerably, especially in the 

 Schizophycete, Chlorophyceae aud Diatoms. A systematic Hst of all the 

 species recorded in the region is given, with references to literature and 

 critical notes ; as well as tables to show their frequency. 



Flora of Great Salt Lake of Utah.* — L. L. Daniels reports on 

 the flora of the Great Salt Lake and the effect, on the organisms, of 

 different densities of the water. He gives first a short summary of 

 previous work on the Salt Lake flora, which appears, like the fauna, to 

 be abundant in individuals, but not in species. The observations made 

 covered a small portion of the southern end of the lake at what is known 

 as Saltair Beach. This is at such a distance from any stream entering 

 the lake that the density of the water there is not affected to any degree. 

 Among the algse found there was a species of Chlamydomonas which 

 N. L. Gardner beUeves to be a new species. It has a rich green 

 colour, and occurs, during the warm weather, on the surface of the water 

 in many more protected places. Another species is Aphanothece 

 PacTcardii (Farlow) Setchell, which occurs in small masses, irregular in 

 size, floating in the water and piled up by the waves on shore. Micro- 

 scopic examination of this material shows the individual plants in a 

 mature condition, and also in various stages of division by fission. Two 

 species of diatoms were found, belonging probably to Navicula and 

 Cymhella. As regards the physiological investigations the results 

 obtained show that variations in density of the water of Great Salt Lake 

 cause no corresponding variations in the size of Chlamydomonas cells. 

 The indication is that water somewhat less dense than that normally 



* Amer. Nat., li. (1917) pp. 499-506. 



