224 EllYOPSIS. PAET ii. 



or less wrinkled and curled throughout. Downwards it 

 tapers to a fine thread, and although attached at first, 

 at last it becomes floating. Several of these plants 

 rise from the same root, sometimes to the height of 

 two feet, at others not more than an inch, and they are 

 of every width, from the tenth of an inch to three 

 inches, their colour being grass green. The typical 

 form of the other group is much branched, and all the 

 branchlets are finely pointed. 



The three genera Codium, Bryopsis, and the marine 

 Vaucherias are all soft plants characterized by their 

 filaments being tubular, however much they may be 

 branched. They agree also in being reproduced by 

 zoospores developed from the green matter within little 

 sacs attached to the exterior of their filaments. The 

 species of the genus Codium differ much, although 

 formed of similar elements. In the C. tomentosum, 

 which is from three to twelve inches long, the dark 

 green stem is thicker than a crow's quill and much 

 branched; while Codium Bursa,on the contrary, is a dark 

 green round spongy lump of tubular filaments, densely 

 interwoven and matted together. These masses, which 

 are from one to eight inches in diameter, become hollow 

 when old, and different sizes and ages grow together in 

 a group. 



The Bryopsis is a yellowish green tubular plant, from 

 two to four inches high, plumed like a feather, and some- 

 times replumed. It is a rare plant in England, and 

 grows on the larger Algse in deep water. 



The Yaucheria marina forms soft limp tuffcs of hair- 

 like filament filled with bright green matter, which often 

 runs partially out. It is from one to three inches high, 

 and has a few long upright branches, to which are 

 attached small stalked pear-shaped sacs containing zoo- 

 spores. Both this plant and the Yaucheria velutina, 

 grow on muddy shores. 



