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tative divisions do not take place any more have the cells usually more 

 short than broad. The relation between breadth and length of the cells 

 in such branches is varying from 1—6. In young branches the cells 

 usually are longer than their breadth especially in the upper part, and 

 the apical cell is up to 8 times longer than its breadth. The sporangia 

 occur in branches of all orders, and are IV2 — 4 times broader than their 

 length or about as broad as long. They occur for the most part singly 

 but two or three sporangia in a continuous row T are also frequent, and I 

 have moreover not seldom met with five emptied sporangia in a row. 

 The opening, through which the spores escape, is rather large and situated 

 in the middle of the 

 cell or nearer the 

 ends. I have not sel- 

 dom seen the adjacent 

 cells , one to each 

 side, growing inwards 

 into the emptied spo- 

 rangia, which at last 

 thus include new ve- 

 getative cells. The 

 cells, which Strom- 

 felt describes as va- 

 cuous and filled with 

 air (1. c. „cellulis una 

 et altera vacuis aë- 

 reque plenis"), are 

 undoubtedly emptied 

 sporangia. The chro- 

 matophores contain 

 many, but not dense, 

 pyrenoids; the large- 

 ness of the meshes is considerably varying in the same cell, especially 

 in the longer cells, which besides small meshes also contain very large 

 meshes. The old branches are never pointed, as in A. albescens Kjellm., 

 but ending in a short apical cell with arched apex (fig. 13, <?). 



Spinous branches or hooked or incurved branches never occur in 

 this form. As the rhizines rarely occur, the plants are little or not 

 entangled below. Fructiferous specimens have been gathered in May— 

 August. 



This form occurs for the most part in the upper sublitoral region. 

 Strömfeit (1. c.) found it loose and floating in the water and both by me 

 and Ostenfeld it has been picked up from a depth of 3 — 4 fathoms. 



a b c d e 



Fig. 13. Acrosiphonia hystrix (Strömf.). 

 a a fragment of a branch showing emptied sporangia 

 into which the adjacent cells grow; h, c, d show the 

 apical cell, in d the apical cell is divided; e the end 

 of a branch in which vegetative divisions do not take 

 place. (15 : 1.) 



