rhodymeniacejE. 163 



This genus and Naccaria, so far at least as the British 

 species were concerned, were formerly combined. Pro- 

 fessor Agardh, in his ' Species Algarum/ has separated 

 them, and as I have been following the arrangement of 

 that work as nearly as possible, I have done so in this 

 particular. The words between inverted commas in the 

 descriptions of these two genera are from Dr. Gray's 

 ' Handbook of British Water- weeds.' 



Atractophora hypnoides. Hypnum-like Atracto- 

 phora. 



Fronds slender, much branched, from two to four inches 

 high, and about the same breadth ; branches alternate, long, 

 spreading ; branchlets slender, jointed, whorled with minute, 

 necklace-like, forked fibres. Spores naked, set among the 

 whorled fibres of the branchlets ; tetraspores unknown. 



This is a recent addition to our list of British sea- 

 weeds. It was first discovered in Jersey by Miss Turner, 

 and has been subsequently found at Exmouth by Mrs. 

 Gulson. It is a very beautiful and distinct plant, and 

 will prove a rich prize to those collectors who may be so 

 fortunate as to find it either in the above or in new lo- 

 calities. 



Obdek XVII. RHODYMENIACEiE. 



Fv/rple or JRed Sea-weeds with a flat, compressed, or tJiread- 

 liTce, membranaceous frond, without joints, composed of 

 many-sided cells, the surface cells forming a continuous 

 coating. Fructification : — 1. Spores in necklace-like, 

 branching threads issuing from a placenta, massed together 

 without order at maturity, lodged in external conceptacles. 



M 2 



