16 BRITISH DESM1D1ACEJ1. 



slightly rounded, sides slightly convex with three 

 undulations between the basal and apical angles, apex 

 truncate and biundulate (sometimes very obscurely). 

 Side view of semicell semi-oblong-elliptic. Vertical 

 view subelliptic, ratio of axes about 1 : 1*5. Cell-wall 

 smooth. Chloroplasts axile, each with one pyrenoid 

 and several longitudinal ridges. 



O O 



Zygospore globose, bearing many short stout spines 

 (almost verrucas), slightly dilated at the base and bi- 

 or tr if urc ate at the apex. 



Length 28-34- 5 /< ; breadth 19-25'3/i; breadth of 

 isthmus 8-16 /u; thickness 14-1 7 /u ; diam. zygosp. 

 without spines 25-26 /u, with spines 3 5-3 6* 5 /u. 



ENGLAND.- -Ogden Clough, Eibblehead, and Cam 

 Fell (with zygospores), AY~. Yorks ! Leicestershire 

 (R<nj). Tintagel and Withiel, Cornwall! 



WALES.- -Radnor ! 



SCOTLAND.- -Inverness, Aberdeen, Kincardine, Forfar, 

 Perth !, Argyll (Roy $ Bissett). Bressay, Shetlands ! 

 Orkneys ! 



IRELAND. --Slievecommedagh, Down ! Dublin and 

 Wicklow (Ai-clier}. 



Geogr. Distribution.- -France. Germany. Galicia. 

 Bohemia (var.). Italy. Norway. Sweden (var.). 

 Bosnia. Nova Zembla. Franz- Joseph-Land. Green- 

 land. E. Africa. Azores. United States. 



C. notabile is a rare species occurring in boggy mountain 

 springs,, in the permanent bogs of heaths, and not uncommonly 

 among mosses on rocks kept constantly wet by trickling 

 water. The width of the isthmus is somewhat variable, but 

 in all specimens of the typical plant the sinus is slightly 

 open. The zygospores we have examined from West York- 

 shire are very similar to those of C. crenatum, and differ from 

 the zygospore of this species figured by De Bary ( Conj/ 

 1858, t. 6, f. 54) in the possession of much more robust 

 spines without any marked basal inflation. 



Forma minor Wille. (PI. LXVI, fig. 17.) 



C. notabile Breb. forma minor Wille, Ferskw. Alg. Xov. Semlj. 1879, p. 36, 

 t. 12, f. 17 ; Cooke, Brit. Desm. 1887, p. 118, t. 42, f. 12 ; De Toni, Syll. 



