GEOGRAPHICAL DISTRIBUTION 



Cockburn Island, 64 S. (a latitude no greater than that 

 of Archangel, where the vine is said to ripen in the open 

 air), and this proved to be an 

 Ulva ( U. crispa*), identical with a 

 small species which may often be 

 seen in this country on old thatch, 

 or on damp walls and rocks, form- 

 ing extensive patches of small green 

 leaves. It is not common to find 

 marine plants with so wide a distribution ; but a nearly 

 equal extent of sea is characterised by another of the 

 British Chlorosperms, of 

 a much greater size and 

 more complex structure. 

 On most of the rocky 

 coasts of Britain may be 

 gathered in tide-pools, 

 or rocks near low- water- 

 mark, an Alga of a bright 

 green colour and spongy 

 texture, cylindrical, and 

 much branched, the 

 bran chesdividing pretty 

 regularly by repeated 

 forkings, and the whole 

 invested, when seen un- 

 der water, with a downy coat of colourless filaments. 

 The name of this plant is Codium tomentosum. Under 

 the microscope it is found to be wholly composed of 



* See " Flora Antarctica," vol. ii. p. 498. In the northern hemi- 

 sphere, Ulva crispa extends to Spitzbergen, in lat. 80. 



DDIUM TOMENTOSHM. 



