220 



starch grains, but in 

 other cases starch is 

 wanting. 



Fructiferous spe- 

 cimens I have had no 

 opportunity to submit to 

 closer examination. The 

 sporangia! conceptacles 

 are, according to Foslie 

 very little prominent, 

 300 — 500/^ in diameter, 

 not overgrown, the 

 sporangia tetrasporous. 



A crust dredged at 

 the beacon of Halskov 

 Rev in Nov. (no. 3171) 

 and referred by Foslie 

 to this species, differs 

 by having overgrown 

 sporangial conceptac- 

 les, but seems otherwise to agree with this species. The conceptacles of sporangia were 

 however a little smaller than usual, 260— 280/i in diameter (inner diameter about 200 //.). 

 The sporangia were tetrasporous, in some cases showing vertical divisions (lig. 137). 



Fig. 136. 



Lithothamnion Sonderi. A, vertical section of frond with .t single-layered hypotlial- 

 liuni. B, thinner crust with two or three layers of cells in the hypolhalllum, con- 

 taining starch grains. C, upjjer part of a thick frond with an uneven surface. 3,')0:1. 



Fig. 137. 



Lithothamnion Sonderi (?), from Halskov reef (no. 3171 ). A, vertical section through a crust with overgrown conceptacles. 

 63:1. B, part of a similar section with an overgrown conceptacle, showing the hypothallium. 350:1. C, sporangial 

 conceptacle with sporangium. 20.'>:1. l)—F, sporangia with anomalous divisions. 205:1. 



