26 BUITISH SEA-WEEDS. 



scientific purposes. In order to avoid carrying home 

 useless matter, which is very detrimental to the examina- 

 tion or successful preservation of specimens, each plant, 

 as it is gathered, should be washed in some shore pool, 

 to free it from sand or other extraneous substance, and the 

 redundant or broken branches should be removed. It 

 should then be placed in the box, in such a manner that 

 it will remain separate and not be damaged by or become 

 entangled with its fellows. Specimens of Desmarestia, 

 Sporochnus, and Arthrocladia must be kept by them- 

 selves, for they not only decompose very rapidly, but 

 also cause other weeds with which they are in contact to 

 do the same. Polysiphonias, Dasyas, and Griffithsias-, 

 indeed most of the more delicate Red weeds, lose their 

 colour if put into fresh-water. They should therefore 

 be kept separate, and I have always found it convenient 

 to carry them in a bottle filled with sea-water. 



There are three modes in which specimens may be 

 obtained, — first and best by gathering them in a growing 

 state ; secondly, by picking up such as are cast on shore 

 by the sea ; and, lastly, by dredging. The two former 

 are more accessible than the latter, and a very large col- 

 lection may be formed by following them. There are, 

 however, a few deep-water species which can rarely be ob- 

 tained, except by means of the dredge. During spring- 

 tides, which occur at new and full moon, many rocks 

 and pools which are ordinarily out of reach may be 

 explored, and the opportunities thus afforded should 

 always be diligently used. Again, after a gale, parti- 

 cularly if it should be coincident with the spring-tides, 

 many rare deep-water species are thrown up, and may 

 be found among the masses of weed left by the receding 

 waves. 



