220 
starch grains, but in 
other cases starch is 
wanting. 
Fructiferous spe- 
cimens I have had no 
opportunity to submit to 
closer examination. The 
sporangial 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 Novy. (no. 3171) 
and referred by FOSLIE 
: : : ARTE le) 190. veal to this species, differs 
Lithothamnion Sonderi. A, vertical section of frond with a single-layered hypothal- 
" lium. B, thinner crust with two or three layers of cells in the hypothallium, con- by having overgrown 
taining starch grains. C, upper part ofa thick frond with an uneven surface. 350:1. 
sporangial conceptac- 
les, but seems otherwise to agree with this species. The conceptacles of sporangia were 
however a little smaller than usual, 260—280,, in diameter (inner diameter about 200 »). 
The sporangia were tetrasporous, in some cases showing vertical divisions (fig. 137). 
Fig. 137. 
Lithothamnion Sonderi (?), from Halskov reef (no. 3171). À, 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. 205:1. D—F, sporangia with anomalous divisions. 205:1. 
