ON SCOTTISH DESMIDIE.'E 245 



yellowish, globular ; between the conjugating fronds ; dia- 

 meter 22^/z. 



24.^ C. incurvum, Breb. Pretty common. Sutherland, Ross, Inver- 

 ness, Nairn, Aberdeen, Kincardine, Forfar, Perth, Stirling, 

 Dumbarton, Fife. 



25. C. intermedium, Ralfs. Widely distributed, but usually scarce. 



Orkney, Sutherland, Ross, Inverness, Nairn, Aberdeen, Kin- 

 cardine, Forfar, Perth, Stirling, Dumbarton, Argyle, Renfrew, 

 Arran, Kirkcudbright. 



With zygospores at Fyvie in Aberdeen. They are thick- 

 walled, yellowish, globular ; conjugating fronds closely 

 adhering, crossed as in C. Leibleinii, etc. Diameter, 

 3 8 -45 /* 



26. C. Jenneri, Ralfs. Not common. Sutherland, Ross, Aberdeen, 



Kincardine, Forfar, Perth, Argyle, Arran. 



27. C.junctdum, Ralfs. General. Three forms of this species are 



common : 



a Ralfs. Empty frond colourless, stride very faint, slightly 

 tapering towards the tips. Length, 110-200 fj. ; 

 breadth, 6-J/i; diameter of smooth, globular, 

 brownish zygospore, 22^/1. 



ft Ralfs. Stouter in proportion to its length, brownish, 

 striee more prominent, slightly tapering. Length, 

 185-275 //, ; breadth, 13 ft; diameter of globular, 

 thick-walled, yellowish zygospore, 40-44 //,. This 

 form seems as closely connected with C. inter- 

 medium, Ralfs, as with the present species, but we 

 have not observed it with more than three sutures, 

 and the striae are fewer. 



y elongatum, n. var. Much elongated, slender, not 

 tapering, brown, stride distinct, few. Length, 355- 

 400 /z ; breadth, 1 1.2/4. Zygospores not seen. 



a was found conjugated in a little marsh on the ascent of 

 Glas Mhoel from the Cairnwell, on the Perthshire side. 

 f3 was gathered with zygospores at Fyvie in Aberdeenshire. 



28. C. Kiitzingii, Breb. Not common. Sutherland, Ross, Inver- 



ness, Aberdeen, Kincardine, Forfar, Fife. 



A single conjugated example of this species was found in 

 a marsh near Gillan in Strachan, Kincardine. Unfortunately 

 it was lost. The zygospore resembled that of C. rostratum, 

 Ehr., more than that of C. setaceum, Ehr. 



29. C. lanceolatum, Kiitz. Very rare. Sutherland near the Falls 



of Kirkaig ; Aberdeen near Haughton, Alford, and Koynach 

 Moor in Cromar. 



