BY G. I. PLAYFAIR. 613 



Genus Cosmarium Corda. 



Cos. submammilliferum West & West j3 quadrigemme mihi. 



Cos. quadrigemme n.sp., in Proc. Linn. Soc. N. S. Wales, 1907, 

 p.193. 



Compare West & West, Journ Bot. xxxv. T.368, f.8. 

 This species is only known besides from South Africa. 



Cos. rectangulare Grun. var. nodulatum, n.var. (Plate xii., 



fig.5). 



Major quam forma typica. Semicellulse lateribus e basi rectis 

 paullo divergentibus; angulis basalibus fere rectis interdum 

 acuminatis et subdentatis; angulis lateralibus obtusis, apicalibus 

 in tumores parvos, glabros, humiles, rotundatos, singulos pro- 

 duces. A vertice semicellulaB latissime-ellipticse, apicibus acumi- 

 natis rotundatis. A latere semicellulse subcirculares latiores 

 quam longa?, sursum tumoribus singulis projicientibus. Mem- 

 brana achroa glabra, grosse punctata, ad angulos basales incrassata 

 ut videtur. Nuclei amylacei bini. 



Long. 54-62; lat. 40-44; crass. 30-36/n. 



Auburn, Guildford (23, 45, 60), cum forma typica. 



The tumours are on the midline of the apex; there are therefore 

 only two to each semicell. With this form compare Cos. repan- 

 dum Nord., Frw. Alg. N. Z. T.6, f. 14; Cos. pseudoprotuberans 

 Kirch., in Wille, Norges Fersk. T.l, f. 18, and /3 angustius Nord., 

 I.e. T.6, f.15,16; also Cos. rectangulare Grun.( = Cos. Gothlandi- 

 cum Wittr., Gotlands Sotv. T.4, f.14). 



Var. Boldtii mihi. 



Cos. rectangulare, forma, Boldt., Desm. Gronl. T.l, f.18. 



Semicellulse a vertice visas late-ovales, apicibus latissime 

 rotundatis, utrinque in medio levissime angulatse. 



Long. 44; lat. 36; crass. 24/x. 



This form undoubtedly belongs here, and not to Cos. subrect- 

 angulare Gutw., Fl. ok. Tarn. T.3, f.23. 



