X ADVERTISEMENT. 



the student must make thin longitudinal and transverse slices, 

 and examine these. Such slices are best made under a simple 

 lens of about 1 or 1^ inch focus, placed on a movable arm over a 

 firm horizontal stage. The best instrument for the purpose is 

 known to London opticians as the " simple botanical micro- 

 scope." The cuttings are made with small, finely edged dissect- 

 ing knives, or may be made with lancets when knives cannot be 

 procured. The object to be cut should be tolerably dry, and 

 about a quarter of an inch long, and is to be held firm on the 

 stage by pressing on it the nail of the forefinger of the left hand, 

 while the cutting is being made with the right hand, the eye 

 being kept closely applied to the lens. If the section do not 

 readily expand in a drop of water, a drop of muriatic acid will 

 often assist the expansion. Some very delicate Callitlt amnio, 

 and Polysiplionia cannot be removed from paper by water ; but 

 fragments sufficient for examination, of most of these, may be 

 loosened (with loss of colour however) by ammonia. 



A collection of Algae may be kept, either in volumes, bound 

 with short interleaves, or in portfolios ; in the latter case the 

 species of each genus should be enclosed in a separate wrapper 

 of stiff paper, of uniform size, the name of the genus to be 

 written on the outside of the wrapper. Where the number of 

 portfolios or genus-papers is large, closed cabinets with shelves, 

 as in an ordinary Herbarium, must be provided. 



Before closing this Advertisement, the Author takes this oppor- 

 tunity of soliciting, from collectors of Alga? resident in Australia, 

 specimens in aid of the work. It is, he trusts, the interest of every 

 Australian Algologist, that a work undertaken to illustrate the 

 Algae of Australia should be made as perfect as possible ; and to 

 make it perfect will require well dried specimens of as many 

 species as can be procured. For even though all be not figured 

 in our volumes, those that are omitted will be briefly described and 

 compared with figures of species they most resemble, in a general 

 Synopsis intended to be prefixed to the last volume. Collections 

 of specimens will therefore be thankfully received and gratefully 



