1897-98-] Microscopic Life. 311 



Pediastrum is a somewhat similar object, but not nearly so 

 beautiful. We have since obtained Volvox from the pond in 

 the Botanic Garden. 



Among the most interesting Algse which we have found are 

 Spirogyra, Schizonema, Nostoc,Ch£etophora,Vaucheria, Batracho- 

 spermum, and Draparnaldia. Spirogyra is very common : as 

 the name implies, the endochrome is arranged in grace- 

 ful spirals in the cells. The number of turns in the cell, as 

 well as the number of threads, vary according to the species. 

 We have frequently found Spirogyra in conjugation, when it 

 presents many curious features : two cells, for instance, may 

 occasionally be seen both trying to reach the same cell in the 

 opposite filament, and when this happens, one or the other 

 will most likely be left out in the cold altogether. 



We found a good deal of Nostoc at Strathpeffer, but have 

 seen comparatively little about here. It is like chains of tiny 

 green beads, and at one period these are coiled up in a mass 

 of transparent jelly. 



My mother brought us our first specimen of Schizonema 

 from the roof of Craigmillar Castle (and who knows but its 

 ancestors may have lived there in Queen Mary's time !). At 

 one stage of its development it spreads out in broad curly 

 fronds, easily recognised by the naked eye, but later on it 

 divides into narrow filaments. These two stages were for some 

 time thought by naturalists to be two distinct plants. 



Chsetophora endivrefolia grows pretty freely in Kavelston 

 Quarry, and is a beautiful object. The filaments are enclosed 

 in a gelatinous thallus very like a tiny endive leaf. In order 

 to get a good view of the separate branches, we found it 

 necessary to press a fragment pretty hard between two glass 

 slides, and hardly too much pressure can be used when a 

 view of the branchlets is wanted. 



Vaucheria is a rather large bright-green alga, not divided 

 into cells, but continuous throughout the filament, and is 

 interesting chiefly on account of its curiously-shaped anther- 

 idia and sporangia : it can almost always be found growing 

 in flower-pots inside any greenhouse. 



We found both Batrachospermum moniliforme and a 

 Draparnaldia in the New Forest : they are closely related, 

 and in both the cells of the main stem are almost colourless, 



