28 BRITISH SEA-WEEDS. 



underneath, he will find a fresh series of interesting 

 forms. That green growth on the exposed part of the 

 wall is composed of three distinct species, belonging 

 to as many different genera. The light green shaggy 

 tufts are Cladophora Icetevirens ; the longer and darker 

 green tubular fronds which grow amongst and over- 

 hang it, are Enter omorpha compressa; and the pendent 

 flat fronds lower down are Viva Linza. The delicate 

 filmy purple plant which is so fragile that it is difficult 

 to gather a perfect specimen, is Porphyra vulgaris ; and 

 closely applied to the wall like a crust, which any but 

 a close observer would overlook, are dark-olive patches 

 of Ralfsia verrucosa, and the harder, calcareous, purple 

 fronds of Melobesia. Near the bottom of the wall are 

 tufts of Chondrus crispus, at present in a young state, 

 with their fronds imperfectly developed. In the pools, 

 and on the larger Sea- weeds, are olive spots of what at 

 first sight appears to be slimy mud, but which, on closer 

 examination, will prove to be Ectocarpus littoralis and 

 E. tomentosus. On the wall and boulders under the 

 Fuci, which protect them from the sun and keep them 

 moist when the tide is down, are lovely Ceramiums 

 and delicate Ca/lithamnions ; each species with a colour 

 and mode of growth peculiar to itself, by which, after it 

 has once been thoroughly studied, it may be readily 

 distinguished. Nor are these all. That smooth dark- 

 green coat on the wall, which has been hitherto over- 

 looked, is a species of Conferva ; and the shining purple 

 spots are Bangia fusco -purpurea, which, though they 

 appear insignificant to the naked eye, have an internal 

 structure that will well reward the trouble of a micro- 

 scopic examination. 



This rough sketch from nature will, I trust, serve to show 



