Acta Societatis pro Fauna et Flora Fennica, 49, N:o 7. 



61 



which it is distinguished by its smooth, undulated (not 

 finely granulate-spinate) processes 3-furcate at the ends. 

 Closely allied is also S. ernstii Bernard (Prot. Desm. Java 

 pi. 11 f. 280—289), which, according to West (Journ. of 

 Bot. 47 page 60), is nothing but 5. tetracerum. Compare 

 also 5. paradoxum v. tosnense Bolochoncew (in Skori- 

 kow, Sommerplankt. Neva p. 391 c. icon.), which differs 

 by its denticulate processes, 4-spinate at the ends and its 

 size, which is the double. [This variety is by no means 

 nearly related to S. paradoxum and should be relegated 

 elsewhere: perhaps as a separate species, perhaps as a 

 variety of S. tetracerum?]. 



Hab. Gov. of Archangel. PI. 5 fig. 36—37. 



S. tetracerum (Kiitz.) Ralfs, Brit. Desm. p. 137—138 

 pi. 23 f. 7. This species is described by Ralfs as having 

 ..processes which are entire at the apex" and the cell-wall 

 as being „rough with minute puncta-like granules which 

 form transverse lines on the processes and give them a 

 jointed appearance". This diagnosis is probably erroneous 

 in one respect: the apex of the processes are, as I should 

 imagine, not entire, but furnished with similar „puncta- 

 like granules". As a matter of fact I have never seen and 

 do not know any Staurastum-species of this group with 

 entire ends of the processes. Perhaps the diagnosis is due 

 to the low magnification by which Ralfs worked. (This is 

 also Dr Borge's opinion.) — An exact information cornern- 

 ing the S. tetracerum is very difficult to get, as no good 

 figures of this species have been published. The best course 

 would be to examine the original specimens of Ralfs or 

 some other classic. 



var. biverruciferum, nova var. Cellulae parvae, medio 

 incisura parva obtusa aperta constrictae. Semicellulae bi- 

 radiatae trapeziformes, dorso glabro concavo, angulis supe- 

 rioribus in radios attenuatos denticulatos denique 3-dentatos 

 productis; lateribus denticulatis; dorso glabro leviter con- 

 cavo; membrana in medio semicellularum verrucis 2 parvis 

 ornata. A vertice visum sexangulare polis utrimque in 



