ON SCOTTISH DESMIDIE^E 237 



ON SCOTTISH DESMIDIE^E. 

 By JOHN ROY, LL.D. 



( Continued from page 1 80. ) 



42. *S. dejectum, Breb. General. Zygospores are not uncommon. 



/3 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. 5. t/ispar, Breb. Not common. Sutherland, Ross, Aberdeen, 



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

 Aberdeen, at Slewdrum. 



46. S. echinatitm, Breb. Very rare. Aberdeen near New Pitsligo, 



and south of Birsemore; Forfar Canlochan; Perth Bracklin. 



47. S. elongatum, Barker (Trans. Dub. Micro. Club, 2 7th May 1869). 



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

 rare. Ross Poolewe ; Argyle Glen Coe. 



48. S. erasum, 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, n //; thickness, 38 - 4/ J t. (Our Plate 

 IV. fig. 3.) 



This somewhat resembles a form figured by Delponte 

 under S. 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, Alford. 



51. S. forficulatum, Lundell. Very rare. Perth near Buchanty, 



and near Fowlis Wester. 



