124 SEA-WEEDS. 



hard and rigid, but when exposed to the air, it 

 droops and becomes soft, and in this state it closely 

 adheres to paper. 



Leaving unnoticed several genera of the Melan- 

 osperms, as being either too rare or too difficult of 

 description without the aid of scientific terms, we 

 proceed to a marine plant which on our rocky 

 shores is common during the summer. This is the 

 Dichotomous Dictyota (Dictyota dichotoma), which 

 has flat fronds from about three to twelve inches 

 long, irregularly cleft, and the segments narrower 

 towards the extremities. It is of a clear olive- 

 green colour, lighter in tint and thinner in texture 

 than most of the olive-green sea-weeds. 



Two frequent plants of our shores may easily 

 be recognised by him who gathers up the stores 

 thrown up by the seas. They are the two species 

 of Sea Whiplash, sometimes called by our sailors 

 sea catgut and sea laces. One kind of this whip- 

 lash (Chorda filum) grows attached to rocks and 

 stones, and is of an olive-green colour, and carti- 

 laginous substance. It waves about under the 

 water like a number of strings, and has generally, 

 at its tip, a bunch of thread-like sea-weed, which 

 is parasitic upon it. This cord is hollow, and inter- 

 rupted at intervals by transverse partitions, which 

 are thought, by Stackhouse, to be designed to 

 confine the air or elastic vapour within certain 

 spaces, so as to act like air-vessels and increase the , 

 buoyancy of the plant. The fronds extend to an 

 amazing length, and always shoot upwards towards 

 the surface of the waters. They are sometimes not 

 more than a few feet long, and are spirally twisted. 

 In its growing state, the whole plant is fringed 

 with small delicate filaments, which render it very 



