taS Mr, TvviT^ER s Defcriptlons of 



which they eflentlally differ, I fhould flill have felt very unwlUing 

 to defcribe them as fpecifically diftin6t, were it not for the curious 

 lines of concatenated veins which I find both pecuhar to this 

 fpecies, and condant in all the fpecimens that have fallen under my 

 obfervation. In a frefh ftate thefe veins are fo eafily vifible, as to give 

 the plant a flriated appearance 5 but when dried, efpecially if faft- 

 ened upon paper, a good glafs and ftrong light are neceffary to dif- 

 cover them. 1 have never been able to form a fatisfai6lory opinion 

 upon the ofBcc which they are intended to perform in the internal 

 orga-nization of the fpecies; nor indeed is this a fubje6\: upon which, 

 in our prefent knowledge of the marine algse, it would be right to 

 hazard aconje6lure. I (hall therefore content myfelf with obferving, 

 that they run from the midrib to the fides of the leaf generally in pa- 

 rellel lines, but fometimes branching and anaftomofing; that they arc 

 quite pellucid; and that they are interfc6led at regular diltances with 

 joints, like the filaments of Cojifervcc, The colour of Fucus rvfcl- 

 foiius is always much darker than that of Fucus Hypoglojfum) the 

 Jeeves of a diiierent form, and, particularly when young, very 

 Hunt; the texture of the membrane, under a powerful microfcope, 

 d-iffimilar; the ftem far ftrongcr; and the midrib more prominent 

 as well as more vifible: to which is to be added, that the months of 

 January and Febru'clr)^are thofe in vrhich this -plant bears its fruit, 

 afid in which it is moll: frequently fcen upon the Yarmouth beach; 

 wliereas Fucns HypGgloJfum fructifies only in the fummcr, and 

 never appears at any other part of the year. Hence I conclude, that 

 the one is annual, the other perennial. I have a fpecimen oi Fucus 

 iufcifdlus with the root completely fibrous; no tendency to which 

 I ever faw in Fucus B.ypogkJJ'urn', but, this not appearing to be al- 

 ways the cafe, I havcriOt confidered a fmgle inftance fuihciently im- 

 portant to ground any part of the fpecific diftinaion upon it. In 

 the mode of frvaifying, the two plants completclv acricc; and, as 

 '^ much 



