— 257 — 



proposing the above name in honour of M me Weber van 

 Bosse 1 ). 



The cells are about half the size of those in D. favulosa, being 

 on an average about 500^ in diameter, fbut varying, many cells 

 being much smaller, others reaching up to 700 — 800 « in diameter. 

 Between the cells rather large 

 intercellular openings often oc- 

 cur in which the hapteræ grow 

 rather long. 



Herewith a short Latin diag- 

 nosis : 



Frons irregulariter rotun- 

 dato-hemisphærica, solida, nun- 

 quam cava, cellulis processibus 

 acutis in pariete interiori instruc- 

 ts, rotundato-polygonatis, me- 

 diocribus, ca. 500 ju latis. 



As to its mode of growth 

 the cell division seems to take 

 place in a similar way to that 

 found in D. favulosa. In any 

 case the three small cells found 

 in the larger one in fig. 8 a 

 may be supposed to have a 

 similar origin and also in the 

 small plant (fig. 7) we see some- 

 thing very similar, but I have 

 only found very few cells in 

 this stage of development and 

 quite young stages not at all. 

 Besides, I am very much in- 

 clined to think, that the cells are 

 also able to divide in a very 

 similar way to that found in 

 Valonia, as now and then on 



Fig. 8. 



Dictyosphceria van Bosseœ n. sp. 



a. part of the thallus seen from above, the cell 

 above has been divided in three cells, b. trans- 

 verse section of a young plant showing the mas- 

 sive thallus. In the interwalls between the cells 

 the hapteræ are seen (10 : 1). 



the cell walls of sectioned plants I have found some smaller roun- 

 dish or oval ceils, reminding one somewhat of the lens-shaped cells 



x ) The Ulva cellulosa Mert. msct. named with a? as a synonym to Valonia 

 favulosa by C. A g ard h is this species, judging from a specimen found in 

 the Herbarium of the Botanical Museum, Copenhagen. 



Botanisk Tidsskrift. 32. Bind. 17 



