42 R. Gronblad, New Desmids. 



with fuchsin and potassium acetate, shows that the basal 

 „pore" has been of a very dark colour like the pores, 

 whereas the inner cell-wall is lighter and the outer nearly 

 colourless. Again, no opening of these basal „pores" could 

 be seen, the nature of them therefore being very doubtful. 

 It is particularly noticeable that the original specimens 

 distributed and described by Hantzsch in Rabenhorst's 

 Exsicc. n:o 1407 (sub nom. Arthrodesmus obsoletus Hantzsch) 

 are furnished with a small but unmistakable spine at each 

 basal angle! Furthermore, these spines were not enclosed 

 in an outer hyaline cell-wall, which could not at all be 

 detected. (The specimens were studied dried but also in 

 cold water). Again, in fresh material an outer cell-wall 

 has been found according to the description by Hantzsch 

 (1. c): „Die ganze Zelle ist mit einer zarten wasserhellen 

 Hulle umgeben, die nur am Einschnitt und um die Stacheln 

 etwas abhebt und daher sichtbar wird." — — „uberwieg- 

 ende Mehrzahl der Exemplare des Stachels ent- 



behrt — ". On the whole, this is a matter which ought 

 to be inquired into. Both stained material and living indi- 

 viduals should be examined. Perhaps there really are two 

 species that have been confused. In any case I do not 

 think the description and the remarks of Messrs West 

 (1. c.) quite correct. They only speak of a „mamillate thick- 

 ening" at the basal angles „which can be quite hyaline with 

 the exception of the conical pore, which then stands out 

 very prominently, and has the appearance of a short 

 spine -". But there is not a word about the outer 



cell-wall! I have never seen living individuals, so I am 

 unable to give my opinion in this question. 



hab. Raikala near Imatra (SE), leg. Hj. Hjelt. PI. 7 

 fig. 58—60. 



C. pseudotinecense, nova spec. Cellulae magnae medio 

 incisura lata leviter constrictae. Semicellulae subpyramida- 

 tae ad apicem versus attenuatae, lateribus sub apice levis- 

 sime retusis, apice late rotundato; a vertice visae circulares. 

 Mombrana sparse porosa utrimque ad isthmum seriebus 



