The Scottish Naturalist. 69 



Nordstedt, which is new to Britain, I am indebted to Mr. \Vm. Archer, 

 Dublin, the eminent algologist. 



Perhaps it may not be thought out of place here to offer a hint or two 

 to intending collectors. 



Desmids are pretty generally distributed, being found in streams, as well 

 as pools, but the most prolific localities will generally be found to be 

 permanent shallow pools on heaths. In such situations, a handful of bog- 

 moss taken out of the water and squeezed into a wide-mouthed bottle will 

 be sure to yield something. Another method, which is often very effective, 

 is to plunge a bottle, mouth downwards, into the water ; on reaching the 

 mud, turn it over on its side, and move it about, just dipping in the mud, 

 when it will fill rapidly. Stripping the submerged stems of aquatic plants, 

 often yields good results, as does also " squeezings " of mosses or algoe, 

 attached to stones in sti'eams. As a rule lakes give poor results, but little 

 pools, on their margins, are worth trying, if the bottom is muddy. When 

 taken home, the bottles should be placed in the light, with the stoppers 

 removed, and the contents examined as soon as possible. If they have to 

 be kept for some time, the most of the water should be poured off, taking 

 care to preserve the sediment, and the water replaced by a weak solution of 

 Acetate of Potash. 



I shall be glad to examine any samples sent to my address, 3 Loanhead 

 Place, Aberdeen, with the view of preparing a supplementary list. 



To those gentlemen, who have kindly assisted me, by sending gatherings, 

 I take this opportunity of tendering my hearty thanks. 



Hyalotheca Ehr. 



1. H. dissiliens Sm. — Athole Forest and east from Falar ; Methven Bog ; 

 Arnbathie, and Durdie Moor ; Glen^hse ; Birnam Hill, and Fowlis Wester. 



2. H. mucosa Mert. — Methven Bog, and Durdie Moor. 



DiDYMOPRIUM Kutz. 



I. D. Borreri^^lh. — Methven Bog, and Rannoch ; Glenshee ; Fowlis- 

 Wester. 



Desmidium Ag. 



I. D. 6'zc'ar/c// Ag.— Methven Bog, Arnbathie, and Durdie Moor; Glen 

 Shee. 



Sph/EROZosma Corda. 



1 . S. vertebratum Breb. — Athole Forest. 



2. S. excavatum Ralfs — Athole Forest. 



Spondylosium Breb. 



I. S. pulckellnni Avc\\Qv. — Rannoch; Glenshee; Fowlis Wester. 

 Some months since, Mr. Aixher sent me siipitate examples of this species 

 from Ireland. They are also stipitate in the Fowlis Wester gathering. 



MiCRASTERIAS Ag. 



1. M. dentiadata Breb. — East from Falar, and in Glenshee ; Methven 

 Bog, and Rannoch ; Birnam Hill. 



2. M. Thoj7iasiana Archer. — Durdie Moor. 



3. M. rotata Grev. — Methven Bog, and Durdie Moor ; Birnam Hill. 



