ON SCOTTISH DESMIDIE^E 237 



ON SCOTTISH DESMIDIE^E. 

 By John Roy, LL.D. 



( Continued from page 180.) 



42. S. defectum, Breb. — General. Zygospores are not uncommon. 



($ patens, Nord. — Aberdeen — Alford and Tomachar. 



43. S. Dickiei, Ralfs. — General. With zygospores, in Aberdeen and 



Kincardine. 



44. S. dilatatum, Ehr. — General. The zygospore of this species is 



rather remarkable. One example of the triangular form was 

 found conjugated near Dinnet in Aberdeen. It is somewhat 

 barrel-shaped, with round ends, and has numerous raised 

 bands, passing longitudinally round it, giving the end view an 

 undulated appearance. Diameter 48 //,. [Our Plate IV. fig. 4.) 



45. S. dispar, Breb. — Not common. Sutherland, Ross, Aberdeen, 



Kincardine, Forfar, Perth, Dumbarton. With zygospores, in 

 Aberdeen, at Slewdrum. 



46. S. echinatum, Breb. — Very rare. Aberdeen — near New Pitsligo, 



and south of Birsemore; Forfar — Canlochan; Perth — Bracklin. 



47. S. elongatum, Barker (Trans. Dub. Micro. Club, 27th May 1869). 



St. terebrans, Nordst. — " Norges Desmid." 1872. Very 

 rare. Ross — Poolewe ; Argyle — Glen Coe. 



48. S. erasiwi, Breb., according to Boldt. — Very rare. Ross — near 



Coul (Mrs. Farquharson). 



49. S. eustephanum, Ehr. — Must be very rare. Perth — Spital of 



Glen Shee (Mr. Wm. West). 



50. S. Farquharsonii, n. sp.— Medium-sized, about as long as broad, 



almost circular, ends slightly depressed ; constriction deep, 

 linear, outer opening small with basal angles acutely rounded; 

 end view triangular, sides slightly concave, angles very 

 broadly rounded; membrane punctate. Length, 54-4^; 

 breadth, 48//,; isthmus, 1 1 /x ; thickness, 38-4 /x. (Our Plate 



IV. fig. 3-) 



This somewhat resembles a form figured by Delponte 

 under .V. orbiculare; but his form, besides being only half the 

 size, wants the depression in the ends — a very characteristic 

 feature. Very rare. Aberdeen — plentiful in the old curling- 

 pond at Haughton, AJford. 



51. S. forfiailatum, LundelL — Very rare. Perth — near Buchanty. 



and near Fowlis Wester. 



