ON SCOTTISH DESMIDIE^E 171 



3. H. widulata, Nordst. — Very rare. Aberdeen — in two pools 

 immediately to the west and north of Loch Dawan. 



This species was detected in Sweden by Dr. Nordstedt in 

 1878, and was published in No. 248 of Wittrock and 

 Nordstedt's "Algae Exsiccatae." It was first collected and 

 identified as a new species about 1870 by Mr. W. Archer, 

 F.R.S., in the west of Ireland ; and was sent to a few of his 

 friends under the MS. name of H. tenuis, but was not other- 

 wise published, though a careful drawing was made at the 

 time. We found it in Aberdeenshire in 1874, and after- 

 wards in North Wales (Plate IV. fig. 1). 



GYMNOZYGA, Ehr. 



G. moniliformis, Ehr. ( = Bambusina Brebissonii, Kg. = Didymoprium 

 Borreri, Ralfs.) — General. With zygospores, in Aberdeen, 

 Kincardine, Perth, and Argyle. 



SPONDYLOSIUM, Breb. 



S. pulchellum, Archer. — Not common. Ross, Inverness, Aberdeen, 

 Kincardine, Forfar, Perth, Argyle. 



This species has been found distinctly stipitate, attached 

 to species of Conferva. Mr. Archer drew my attention 

 to this. 



SPH&ROZOSMA, Cor da. 



1. S. Archeri, Gutwinski ("Flora Glonow Okolic Lwowa," Tab. I. 

 fig. 4, p. 29, 1891 ; Nordstedt in Witt, and Nord., "Alg. 

 Exsic," No. 967, 1889, under Sphcerozosma vertebratum 

 (Breb.), Ralfs. Forma ; and Nordstedt in " Alg. Aq. Dulcis 

 Exsic," Fascic. 21, p. 34, 1889. — Very rare. Aberdeen — 

 pond at Tonley, near Alford, where it is abundant ; and 

 near Castleton, Braemar, where we first found it, very 

 sparingly, in 1878. 



Nordstedt and Gutwinski think that probably this is the 

 species Archer had in view as having a spiny zygospore. 

 I scarcely think so, for he makes no mention of the two 

 rows of granules on the semi cell, which he wis far too good 

 an observer to miss. Biene's form ( Kabenh. "Alg. Europ./' 

 NO. 1769) is so completely shrunk, that no amount of coax- 

 ing will show the true form of the cells ; hut no trace of 

 granules can be seen on them. The probability, therefore, 

 is that his form and Archer's are the same. 



