1909-1910-] A IgcB and their Study. 235 



naked eye, have been treated in extenso, while the Green Algae, 

 and especially the Cyanophycese, cannot be studied from these 

 works at all. It is perhaps surprising that long ago two 

 classes of very small and therefore microscopical Algse had 

 received greater attention than the other members of - this 

 group, and we are in possession of some very good systematic 

 works on them. These two are the Diatomacese or Diatoms 

 and the Desmidiacese or Desmids, but as both these have been 

 excluded from the prize collection, I need not mention them 

 further. 



In considering the collecting and subsequent study of Algse, 

 there is one disadvantage very apparent. Excepting always 

 the larger seaweeds, which can and have been for a long time 

 collected and mounted in herbaria exactly as is done by so 

 many amateur botanists with the Phanerogams or flowering- 

 plants, it is evident that we are not able to enjoy the fruits of 

 our labours until we have returned from our excursion. This 

 fact, no doubt, accounts to a great extent for the preference 

 given to the study of the higher plants, as well as the other 

 Cryptogams, such as the Lichens, Mosses, Liverworts, and Ferns. 

 On the other hand, an hour's collecting in a suitable place, 

 such as a pond or moor, will give us a great many hours of 

 enjoyment in examining the various species we may have 

 gathered. Even those who do not care to study their most 

 varied life-histories are obliged in a great many cases to await 

 the reproductive stages in their cultures, as otherwise it would 

 be impossible to determine the species they wish to preserve. 

 It is no doubt a great advantage in favour of our study that 

 most fresh - water Algae can easily be cultivated at home. 

 Small glass vessels or tubes will be found sufficient in most 

 cases, and large aquaria are not required. It is surprising 

 how some species will thrive in small test tubes, or even on 

 a slide kept in the so-called " moist chamber," for a length of 

 time. An exception to this rule we find in those Algae which 

 occur in swiftly running water, but it is only to be expected 

 that they will not outlive the lack of oxygen due to the stag- 

 nant water of an aquarium. 



I think before enumerating briefly the great number of 

 forms which we find among the Algae, and also the extra- 

 ordinary variety of methods their reproductive activity shows, 



