172 ANNALS OF SCOTTISH NATURAL HISTORY 



2. S. excavatum, Ralfs. — General. Frequently conjugated, especi- 



ally among stones in the margins of streams. 



P Walltchii, Jacobs. — Probably not uncommon. Inver- 

 ness, Aberdeen, Kincardine. 

 y Wallichii has been observed on Deeside, and is 

 probably common. 



3. S. gramrtatum, Roy and Bisset. — Widely distributed, but not 



common. Sutherland, Inverness, Aberdeen, Kincardine, 

 Forfar, Perth, Argyle. 



4. S. secedens, De Bary. — Very rare. Aberdeen — at Slewdrum in 



Birse, Loch Dawan, and Mosston Moor in Cromar. 



5. S. vertebratum (Breb.), Ralfs. — Not common. Aberdeen, 



Kincardine, Forfar, Perth. 



ONYCHONEMA, Wallich. 



1. O. filiforme, Ehr. (Spharozosma, Aut.) — Not common. Ross — 



near Strathpeffer ; Inverness — Lochs Ruthven, Aschie, and 

 Coire, etc., near Brin ; Aberdeen and Kincardine have 

 numerous localities. 



2. O. lave, Nord. — Extremely rare. Found once. Aberdeen — 



by the side of the old road from Aboyne to Kincardine 

 O'Neil, about a mile from Aboyne. 



3. O. Nordstedtituia, Turner. — Not common. Probably occurs 



more frequently than its near relative O. filiforme ; but its 

 separate distribution was not noted till recently. 



MICRASTERIAS, Ag. 



1. M. americana (Ehr.), Ag. — Rare. Aberdeen — Scotston Moor, 



Powlair, south of Birsemore, Slewdrum, Morven, Lochnagar, 

 corrie of Loch Ceanmhor ; Kincardine — Glen Dye and 

 Clochnaben ; Forfar — Lundie Bog near Menmuir ; Perth — 

 Glen Shee and Glas Maol. 



f3 Ralfs. — Very rare. Aberdeen — Corrie of Loch 



Ceanmhor ; Kincardine — Crathes, and about Cam- 



mie in Strachan. 



2. M. angulosa, Hantz. — Not common. Sutherland, Ross, Inver- 



ness, Aberdeen, Kincardine, Forfar, Perth, Argyle. 



Conjugated at Slewdrum on Deeside. Zygospore large, 

 globose ; spines stout, bi-, tri-, and quadri-furcate at their 

 apices, and not very numerous. Diameter, without spines, 

 1 1 4-1 16 [x ; length of spine, 32 /x (Plate IV. fig. 2). 



3. M. conferta, Lundell. — Rare. Inverness — Glen Urquhart ; 



Aberdeen — Upper Powlair in Birse, Birsemore Loch and 

 Dalwhing near Aboyne, pool north of Loch Dawan, and 



