ON SCOTTISH DESMIDIE/E 167 



pendium " to the " Cybele Britannica." The following may 

 be quoted here : 



Lyclmis dmrna, at 3500 feet, on Lochnagar. 

 Geranium sylvaticum, at 3200 feet, on Lochnagar. 

 Salix arbuscn/a, at 2550 feet, on Little Craigendal. 

 Poa pratensis (typical), at 2900 feet, on Morven. 



JAMES W. H. TRAIL.] 



ON SCOTTISH DESMIDIEyE. 

 By the late JOHN ROY, LL.D., and J. P. BISSET. 



\_Continued from page 1 05.] 



85. C. margaritatum (Lundell), Roy and Bisset (" Jap. Desm.," 1886, 



p. 194=6*. latinii, ft niargaritatuni, Lundell). 



Large; about one-third longer than broad ; sides very slightly 

 rounded, nearly straight, gradually curving upwards into the 

 broadly rounded ends ; constriction moderately deep, narrow, 

 not opening widely outwards; semi-cells with the base slightly 

 reniform, and not increasing in width upwards; densely covered 

 with large granules, having a punctum in the centre of the space 

 between every three granules ; the granules are arranged in 

 about thirteen perpendicular rows, of about eight in a row, 

 and leaving a small space at the base smooth ; semi-cells in 

 side view nearly circular, and in end view oval. Length, 78 ^ ; 

 breadth, 58 /u, ; isthmus, 27 /^. (Our Plate II. fig. 12.) This 

 form seems sufficiently distinct to constitute a good species. 

 The resemblance to C. latum is not striking. It is consider- 

 ably smaller, and has larger granules, while the puncta be- 

 tween granules is a marked and invariable feature. Rare. 

 Ross pool near View Rock, Strathpeffer (Mrs. Farquhar- 

 son ; Aberdeen Slewdrum in Birse, Aboyne, Cambus- 

 o'-May, and Dalbagie near Ballater, Glen Clunie, one mile 

 from Castleton. 



86. C.wargarztifert/?;/(Turp.), Menegh. General. With zygospores, 



in a small pool at the side of the Deeside turnpike road, 

 about half-way between Banchory and Bridge of Potarch, and 

 south of Birsemore. 



87. C. iiiclanosporum, Archer. Small; length and breadth equal; 



semi-cells transversely oblong ; constriction moderately deep, 

 close, opening out widely into the rounded sides ; ends 

 broadly rounded ; semi-cells from side view circular, from 



