NULLIPORES. 109 



plant, which in some form or other inhabits the shores 

 of most temperate latitudes. 



Along with Corallina officinalis, and also creeping 

 among the roots of various other Algse, may often be 

 seen the fronds of a lichenoid species of calcareous plant, 

 Melobesia (or Nullipora) lichenoides, affixed to the sur- 

 face of the rocky soil. This is of the same family as the 

 Corallina, but simpler in structure. By some authors 

 it is supposed to be merely the imperfectly-developed 

 state of a Coralline ; but the evidence for this opinion 

 does not appear satisfactory, and in the imperfect state 

 of our knowledge it is better to consider these plants 

 distinct. In appearance they are widely different, 

 though similar in microscopic structure and substance. 

 The Melobesia belongs to a group of the family, cha- 

 racteristic of a deeper water, and which we shall have 

 occasion to speak of in our chapter on Dredging. 



The very imperfect outline which I have just given of 

 the several groups of marine plants, is all that the plan 

 of this little volume admits of, without trenching too 

 much on subj ects of perhaps more general interest. The 

 great elegance of many of the sea-weeds, and the ease 

 with which specimens may be preserved, retaining much 

 of their original beauty, attract many persons who 

 occasionally visit the sea-shore ; and sea-weeds are col- 

 lected either as objects of scientific interest, or for the 

 manufacture of pictures for albums or screens. Those 

 who collect sea-weeds for the latter purpose, in general 

 care little to know their history ; but perhaps when 

 some of its facts are known, they may be regarded 

 as not without interest. I have, therefore, mentioned 



