ON SCOTTISH DESMIDIE^E 45 



35. C.cristatnm, Ralfs. Very rare. Aberdeen Steps, Glen Tanner; 



Kincardine Cammie ; Perth Ben Lawers. 



36. C. cruriatum, Breb. Not common. Aberdeen Alford ; Kin- 



cardine Cammie, Cowie, etc. 



37. C. cructferum, De Bary. Not common. Aberdeen Loch- 



nagar, etc. Kincardine Durris, etc. ; Perth in Rannoch. 



38. C. cucumis, Corda. General. 



Forma major, Nordst. Pretty common. 

 ft helvcticum, Nordst. Not common. Inverness, Aber- 

 deen, Kincardine. 



39. C. cucurbita, Breb. General. 



40. C. cyclicuin, Lundell. 



ft arcticuin, Nordst. - - Rare. Aberdeen, Kincardine, 

 Forfar, Renfrew. 



41. C. cylindricuin, Ralfs. Not common. Aberdeen, Kincardine, 



Forfar, Perth, Arran. 



42. C. cytnatophurum, Nordst. 



ft tyrolicum, Nordst. Very rare. Aberdeen near 

 Aboyne, Corry of Loch Kandor ; Forfar in Can- 

 lochan, where it is associated with C. Archcrii. 



43. C. Danicutii, Boerg. Very rare. Aberdeen near Alford. 



44. C. Davidsonii, n. sp. Medium sized, hexagonal, sides and ends 



undulated, the undulations increasing in size upwards, and 

 having the crenate, truncate end produced ; constriction, 

 straight, narrow, not deep ; lower angles acute ; sides nearly 

 straight, converging upwards, with about four undulations ; 

 upper angles rounded ; ends broad, straight, with two un- 

 dulations ; from all the undulations, rows of minute granules, 

 about three in a row, extend inwards, radially, a very short 

 distance ; centre of semi-cell smooth ; isthmus broad ; starch 

 granules single. Length, 37-40^; breadth, 25-26^; 

 isthmus, 1 5-1 6 /z. (Plate I. fig. 8.) 



Rare. Aberdeen at Press Whin, on Morven, and near 

 Aboyne ; Kincardine near Gillan in Strachan Forfar 

 near Balquhadly in Fern, and in Canlochan. 



45. C. De Haryi, Archer. Not common. Inverness, Aberdeen, 



Kincardine, Perth, Kirkcudbright. 



46. C. dentiferum, Corda. Very rare. Has been passed over as a 



form of C. latuni. It occurs both in Aberdeen and Kin- 

 cardine. At present localities are doubtful, 



47. C. dcpressitni, Nag. Not common. Sutherland, Ross, Inver- 



ness, Aberdeen, Perth. 



