ADVERTISEMENT. Vll 



panied when necessary with such magnified dissections as will 

 enable any one possessed of a microscope to refer with certainty 

 the figure before him to the plant which it represents. Un- 

 fortunately — as some may think — for the amateur, the classifi- 

 cation of Algae is based on characters which it often requires a 

 microscopic examination to ascertain. This presents a difficulty 

 at the outset, which is only gradually overcome as the student's 

 knowledge of types of form becomes extended. After all, how- 

 ever, the generic types are not very numerous, and when once 

 known, are easily remembered and discriminated. 



The number of species of Algae dispersed along the Aus- 

 tralian coasts may perhaps be estimated at nearly 1000: the 

 number actually known is about 800. To figure each of these, 

 on a separate plate, would too greatly enhance the price of the 

 work, and place it beyond the reach of an ordinary purchaser. 

 It is therefore proposed to limit the number of Plates to 300, 

 and to select, from the ample materials supplied by the Dublin 

 University Herbarium, such forms as are most characteristic of 

 the Australian Marine Flora, care being: taken to figure at least 

 one species of every genus. Figures of many Australian Algae 

 have already been given in the Author's ' Nereis Australis,' 

 and in the ' Flora Nov.e-Zelandle ' and ' Flora Tasmania ' 

 of his friend Dr. Hooker. As a general rule, species figured in 

 these works will not be repeated ; but exceptions will be made 

 in favour of some characteristic types of form which cannot be 

 omitted without injury to the scope of the present work. 



It may be well to give, in this place, for the use of young 

 collectors, a few plain directions for the collecting and pre- 

 serving of Marine Algae. 



Algae are to be sought either in their place of growth, on the 

 rocks and in the rock-pools left bare or accessible at the fall of 

 the tide ; or in the rejectamenta thrown up by the waves on 

 sandy beaches, or among drifting masses of weed and tangle that 

 sometimes accumulate between two strong currents ; or the 

 deep-water species may often be procured by the use of a 



