364 The Alga-Flora of Mid- Lothian. [Sess. 



occurred in enormous quantities in the plankton of Dudding- 

 ston Loch in July 1911. 



69. Eudorina elegans Ehrenb. 



Bavelaw Moor, April ; Duddingston Loch, July ; Craiglockhart 

 Pond, August and September. 



70. Volvox glohator (L.) Ehrenb. 



I had searched for this Alga, which has occurred in enormous 

 numbers in the Upper Elf Loch in some former years, without 

 result, until I found it in the plankton of Duddingston Loch 

 in July of this year (1911). Mr J. Lindsay, who searched for 

 it in the same loch early in August, also obtained it in fair 

 quantities. It is a well-known fact that this beautiful motile 

 Alga seems to appear suddenly in great numbers, and to dis- 

 appear just as suddenly for several years. 



Family — Endosphaeraceae. 



71. Chlorochytrium Lemnce Cohn. 



On leaves of Lemna trisulca. Duddingston Loch. July. 



72. Chi. Knyanum Szymanski. 



On leaves of Lemna minor. Elf Loch. August. 



Family — Charaeieae. 



73. Charadum Sieholdii A. Br. 



Growing on other Algae. From ditch near Harelaw Eeservoir. 

 August. 



74. Ch. apiculatum Eabenh. 



Esk near Musselburgh. July. 



75. Ch. Pringsheimii A. Br. 



Common. Elf Loch ; Craiglockhart Pond ; Colinton Dell ; Bave- 

 law, &c. Growing on GEdogonium and Rhizoclonium. 



Family— Pleurocoecaceae. 



76. Pleurococcus vulgaris Menegh. 



This is without doubt the commonest of all Algae, forming the 

 well-known green film on trees, walls, palings, rock-faces, &c. 



77. Trochiscia reticularis (Eeinsch) Hansg. 



Bavelaw Moor. April. 



78. Hormotila mucigena Borzi. 



Damp wall of hothouse, Leith. July. 



Family— Hydrodictyaeeae. 



Sub-Family — PEDiASTREiE . 



79. Pediastrum Boryanum (Turp.) Menegh. 



Elf Loch ; Craiglockhart Pond ; Duddingston Loch (plankton in 

 July) ; Bavelaw Moor. May- August. Common. 



