22 BRITISH DESMIPIACE/E. 



most probably a very erroneous drawing of Euastrum ansa- 

 tum Ralfs. 



It is a variable species with regard to the depth of the 

 sinuatioiis of the margins,, and for this reason we have included 

 " var. Falesiensis Breb." as part of the type. 



The five protuberances,, three basal and two central, some- 

 times each possess a conspicuous central scrobiculation, and 

 rarely, similar scrobiculations are found between the pro- 

 tuberances. 



The zygospore of E. sinuosum var. simplex Mask, has been 

 described and figured as " globose, with simple stout spines." 

 Consult Maskell, ' Further Notes New Zeal. Desm/ 1888, 

 p. 11, t. 1, f. 6. 



Var. reductum West & G. S. West. (PL XXXVI, 



%s. 2, 3.) 



E. sinuosum var. reductum West & G. S. West, Welw. Afrie. Freshw. 

 Alg. 1897, p. 83 ; Desm. Singapore, 1897, p. 160, t. 8, f . 17 ; Freshw. 

 Alg. Ceylon, 1902, p. 148. 



Cells somewhat smaller than in the type, polar lobe 

 not dilated, lateral lobules less prominent ; in vertical 

 view protuberances considerably reduced, and polar 

 lobe quadrate-oblong without emarginate poles. 



Length 46-59 /x; breadth 24-32 g o /A ; breadth of 

 isthmus 7'5-9'5 /x ; thickness 15-18/x. 



EXGLAXD.- -Thursley Common, Surrey ! 



IRELAND. Ballvnahinch, Galway ! 



I V 



Geogr. Distribution. Ceylon. Singapore. T\ T . Africa. 



10. Euastrum Jenneri Arch. 

 (PL XXXVI, fig. 4.) 



Euastrum circulare var. j Ralfs, Brit. Desm. 1848, p. 85, t. 13, f. 5 c. 



E. circulare var. Ralfsii Breb. Liste Desm. 1856, p. 122 ; Rabenh. Flor. 

 Europ. Algar. Ill, 1868, p. 183 ; Cooke, Brit. Desm. 1886, p. 72, t, 34, 

 f . 4 ; Nordst. Index Desm. 1896, p. 150 ; West & G. S. West. Alga-fl. 

 Yorks. 1900, p. 62. 



E. Jenneri Arch, in Pritch. Infus. 1861, p. 730. 



This species differs from E. sinuosum in the broader 

 polar lobes; in the larger lateral lobes, which are 

 more quadrate, with equal lobules ; and in the surface 

 protuberances, of which there are eleven, a basal row 



