The substance is leathery when fresh, rigid and rather brittle when dry, in 

 which state the frond does not adhere to paper. 



At Plate XXIV. we have figured a broad-leaved species of 

 Myriodesma, with which our present plant, for which the genus 

 was founded, may be contrasted. Besides the narrow lamina, 

 which in itself would be hardly sufficient to mark a species, M. 

 serrulata is known from M. latifoUa by the single series of spore- 

 cavities at each side of the midrib. In other respects, except in 

 size, the two nearly agree. 



M. serrulata, though long known, appears to be rather a rare 

 species ; unless indeed, as sometimes happens, it is often neg- 

 lected by collectors. I may here be allowed to express my 

 regret, that few of my obliging correspondents in the Colonies 

 are careful to seek out and preserve the brown or fucoid Algae 

 sufficiently. 



rig. 1. Myriodesma serrulata, the natural size. 2. Portion of a serrated 

 lacinia, showing the spore-cavities. 3. Section through two spore-cavities 

 (empty) : — magnified. 



