The name Metachroma, proposed by me for the plant here 

 figured, must yield to the one now adopted from Areschoug, and 

 which has the right of priority by some few months, as I under- 

 stand from a letter from my friend Dr. Sonder, for I have not 

 yet received Professor Areschoug's memoir above quoted. "Me- 

 tachroma " was intended to allude to a remarkable change of 

 colour observed in the living plant, similar to what takes place 

 in Sporochmis, but not so permanent ; for here the olive returns 

 after the specimen is dried, and subsequent moistening does not 

 bring back the verdigris-green. 



Lobospira is readily distinguished from Dicfyofa by the pre- 

 sence of a valid nerve, and by the cartilaginous stem and pinna- 

 tifid (subdichotomous) habit. When growing, it has more the 

 aspect of a small Cystoseira than of a Dictyoteous plant. 



I am not aware of the locality of Areschoug's specimens, and 

 only myself collected this Alga in Western Australia, where it is 

 very common, though hitherto overlooked. 



Fig. 1. Lobospira btcuspidata, — the natural size. 2. One of the ultimate, 

 spirally twisted, pinnatifid branchlets. 3. A fertile pinnule, with a sorus. 

 4. A spore : — the latter figures variously magnified. 



