stance at first cartilaginous, firm and elastic, but soon, on removal from the 

 water, becoming flaccid. Colour, when growing, a clear olive brown, soon 

 becoming verdigris green in the air, and when preserved in the herbarium 

 usually a yellowish olive. 



A very elegant plant, one of the most beautiful of our olive 

 coloured Algae, and not uncommon on any of the British shores. 

 It was first described by Lightfoot in his ' Flora Scotica,' where 

 an excellent figure is also given. With a perfect regularity in 

 its branching, and in all the lesser details of its habit, there is so 

 much difference in the relative breadth of the frond, that speci- 

 mens from different parts of the coast have a very opposite 

 aspect. In some the branches are broader than our larger 

 figure represents, and these approach the narrower forms of the 

 exotic D. herbacea, whose broader varieties have branches as wide 

 as the laciniae of a Laminaria ; in others the frond is so narrow, 

 that, as Mr. Turner well observes, such individuals may, at first 

 sight, be mistaken for luxuriant fronds of D. viridis, whose 

 narrower varieties are as delicate as the finest Conferva. One 

 would scarcely expect this close connection by comparing merely 

 typical states of these three species, but by an extensive suite of 

 specimens the approximation may be very clearly shown, but it 

 never arrives at the point where one absolutely passes into the 

 other. 



Desmarestia ligulata is widely distributed in the Northern 

 Atlantic, and probably as common on the American as the 

 European side, though we have as yet no evidence of the fact. 

 In the southern hemisphere I am only aware of its having been 

 found at Cape Horn, where Dr. J. D. Hooker dredged, from a 

 considerable depth, specimens in all respects similar to British 

 individuals. This fact is the more interesting because the same 

 locality furnishes another closely analogous, but perfectly distinct 

 species, D. Bossii, which, but for the presence of the true 

 D. ligulata, one would be inclined to regard as its representative. 



Fig. 1. Desmarestia ligulata, part of a frond. 2. A branch of a narrower 

 individual: — both of the natural size. 3. A cross section of the lower part 

 of the frond : — m 





