30 BRITISH DESMIDIACE.E. 



SCOTLAND.- -Sutherland!, Inverness!, Aberdeen, Kin- 

 cardine, Forfar, Pertli !, Argyll (Roy Bissett). Outer 

 Hebrides ! Shetlands ! 



IRELAND.- -Donegal ! Mayo ! Gal way ! Kerry ! 

 Dublin and Wicklow (Archer). Lougli Neagh, Antrim. 



Geoyr. Distribution.- -France. Germany. Austria 

 and Galicia. Italy. Norway. Sweden. Denmark. 



Bornholm. S. Russia. Greenland. Ceylon. United 



/ 



States. Brazil. 



Although widely distributed in the older bogs, C. cm ionium 

 is a very uncommon Desmid. Apart from the variation 

 exhibited by the sinus, the cell has a very characteristic 

 shape. 



The granulation is not altogether uniform, and the vertical 

 series are often very indistinct. Near the base of the semicell 



v 



the granules are often associated in pairs, usually in a more 

 or less irregular manner, but sometimes with sufficient 

 regularity to give the appearance of a basal ring of paired 

 granules. This feature may be present to a greater or less 

 extent on one or both semicells, but owing*- to its oreat 



' O O 



variability is of little importance. 



C. amuenum var. annulatum Eichl. & Gutw. (^ISTonn. spec, 

 alg. nov.' 1894, p. 163, t. 4, f. 5), by reason of its general 

 proportions, the form of its sinus, and the fewness of its 

 granules, should be relegated to C. pseudmoenum var. 

 basila/re Nordst., notwithstanding the fact that two pyrenoids 

 are present in each semicell. In very closely allied forms too 

 much importance should not be placed upon the presence 

 of solitary or binate pyrenoids in axile chloroplasts. [Consult 

 Gosmarium subcostatum, C. subcostatum forma minor, and 

 C. subcostatum var. Beckii in Vol. Ill, pp. 236-239.] 



C. amoenum var. Lundellii Rov & Biss. (' Scott. Desm.' 



V 



1894, p. 42; C. amoenum forma major Lund. 'Desm. Suec.' 

 1871, p. 46), which Messrs. Roy and Bissett record from 

 " Ross, Inverness, Banff, Aberdeen, Kincardine, Forfar, 

 Perth, and Stirling," appears to us to be very near to, if not 

 identical with C. sphseroideum West (1892). Its characters 

 were very briefly indicated by Lundell, and not at all by 

 Messrs. Roy & Bissett, so that it is difficult to make certain 

 of this identity. It should be pointed out that C. xpluvronlrtim 

 differs from C. amvenum in its somewhat larger dimensions, 

 its greatly inflated semicells, and in the larger and more 

 flattened granules. 



