144 BRITISH SEA-WEEDS. 



I insert this species in deference to the authority of 

 Dr. Gray's Handbook, from which I have copied the de- 

 scription almost verbatim. Dr. Gray speaks of it as 

 identical with the variety of N. laceratum figured in the 

 ' Phycologia Britannica/ plate 267 ; but he also says that 

 it has no veins, which the figure referred to certainly has. 

 I have examined several specimens in my own collection, 

 but have not yet convinced myself that they are suflS- 

 ciently distinct to be considered more than a very pecu- 

 liar form of N. laceratum. 



Nitophyllum versicolor. The changeable Nito- 

 phyllum. 



Fronds broadly fan-shaped, dichotomously divided, vein- 

 less, expanding suddenly from a tuberous cylindrical stem, 

 about one and a half to two inches high, and one to two 

 lines thick ; the tips of the frond, and sometimes the 

 side margin, are much thickened, and produce oblong, fleshy 

 excrescences, which, as they advance in age, lengthen into 

 irregularly branched, cellular, cylindrical filaments. Fructi- 

 fication unknown. 



The slightest contact with fresh water changes this 

 plant from red to bright orange, but the original colour 

 is restored and retained when the plant is dry. Tt is very 

 rare, and the only specimens hitherto found have been 

 thrown up from deep water on the coasts of Ireland and 

 Devonshire. 



Genus LIII. CALLIBLEPHAEIS. 



Frond flat, membranaceous, irregularly cleft, fringed with 

 marginalJobes, without veins or midrib. Fructification of 



