INTRODUCTION H 



manner for herbarium specimens so that all data on any particular spe- 

 cies are immediately accessible. The figures for the plates of this work 

 have been redrawn from camera lucida sketches made in field labora- 

 tories. The confined space of a vial is not favorable for algae and the 

 more delicate forms, as Uglenopsis, frequently go to pieces after stand- 

 ing a few hours. It is impossible to have the vials uncorked while 

 transporting them from station to station but they should be opened 

 immediately on return to field headquarters. I have also found it 

 helpful to keep them as cool as possible and have stored them in hotel 



I 



refrigerators until ready to make observations. Formalin has proven 

 a satisfactory means of preserving the desmids and diatoms until their 

 study can be taken up during the winter months. 



The following list of simple reagents is helpful in studying the vari- 

 ous structures of living algae. Cilia of motile forms are more easily 

 seen when the cells have been rendered immobile by mounting in a 1% 

 cocaine solution. Mounting in a dilute aqueous acid fuchsin also helps. 

 Pyrenoids can be recognized by the grouping of the starch grains when 

 the latter have been stained with iodine. It is difficult to strain pyre- 

 noids of living cells. Gelatinous envelopes are best demonstrated by 

 Errera's method of mounting in dilute India ink which gives the col- 

 orless envelope the appearance of a halo around the cells in contrast 

 to the dark background of water containing the ink. Nuclei can be 

 demonstrated by Strasburger's solution of methyl green in 1% acetic 

 acid. Simple microchemical tests are Sudan III for fats, iodine for 

 starch, zinc chloriodide for cellulose, and Ruthineum Red for pectin. 



Lakes studied. The following table gives a list of lakes in the state 

 from which plankton samples have been taken. All known hydro- 

 graphic maps, morphometric data, general descriptions of many lakes 

 and general maps of the various lake areas have been given by Birge 

 o,nd Juday* so that any one wishing further data concerning a particu- 

 lar lake is referred to their work. They have not, however, mapped or 

 discussed many of the smaller lakes of the northern regions. Since 

 most of the lakes in the state were named by the settlers of the region 

 considerable poverty of vocabulary is noticed and Round, Mud, Devils, 

 Long, and Sand are repeated many times. In other instances Indian 

 (Chippewa) names have been retained as the white man settled the 

 region. In these also there is a certain amount of duplication and 

 Sishebogema (lake with many bays) or Pokegama (side or branch lake) 

 may be cited as examples. It is too bad that these names have not been 

 retained to a greater extent, but certain of the English names like 

 Razorback, Crawlir^ Stone, Lost Canoe, Tenderfoot or Fishtrap are not 



* Birge, E. A. and Juday, C. The inland lakes of Wisconsin. Bull. 27: Wis. 

 Geol. & Nat. Hist. Survey. (Sci. Ser. 9). pp. 1-137. 1914. 



