20 Transactions of the Society. 



Micrasterias radiosa Ealfs, var. punctata no v. var. This 

 differs from the usual forms of M. radiosa in having a dis- 

 tinctly punctate cytoderm with the division of the lobes 

 more like those of M. papillifera Breb., especially the 

 ultimate ones. The general outline is also more angular. 

 The deeper incisions of the frond are more in accordance 

 with the figures in Cooke's ' British Desmids ' than WoUe's 

 figures. This species was compared with typical M. 

 papillifera Breb. from the same district, but the latter was 

 quite different in showing the rows of dots bordering the 

 chief incisions, as well as in its different size, margin, and 

 shape. The specimen figured had an eighth part of 

 the teeth of the denticulate periphery doubly notched. 

 Fig. 12. 



M. papillifera Breb. Frequent. 



M. rotata Ealfs. 



M. fimhriata Ealfs. 



M. Americana Ktitz. 



M. erenata Ealfs. 



M. truncata Ealfs. 



Staurastrum muticum Breb. 



S. angulatum nov. sp. Semi-cells smooth rhomboid, with a 

 faint indication of an obscure mucro, end view triangular 

 with concave sides. Length 76-78 //.. Breadth 60 fju. 

 Breadth of sinus 17-18 yu,. Seen very sparingly. Fig. 20. 



;S^. polymorphum Breb. Both trigonal and tetragonal end 

 views were seen ; the processes were narrower than usual. 



8. muricatum Breb. 



S. rugulosum Breb. 



S. punctulatum Breb. 



S. pygmseum Breb. Abundant. 



S. alternans Breb. ^ 



;S^. Meriani Eeinsch. This was the typical form agreeing with 

 both Eeinsch's figure and that of Wolle, not like that of 

 Cooke in ' British Desmids.' The end view was pentagonal. 

 One is shown in Fig. 22. 



S. Sehaldi Eeinsch. This seems to be a variable species, as 

 Wolle remarks, so I deemed it worth while to give figures 

 representing the only form I saw. This is nearer to 

 Wolle's figures than the original ones of Eeinsch, the end 

 view has the processes longer than they are shown in the 

 figures given by Wolle. I have British examples of this 

 species collected by Wills, J. H. Lewis, and my son G. S. 

 West, in all of which the arms are very much longer in 

 end view, as figured in Cooke's ' British Desmids ' as var. 

 ornatum Nord. Fig. 17. 



S. teliferum Ealfs. This was fine and like the form I find in 

 Britain as figured in Cooke's ' British Desmids,' not like the 



