250 BRITISH SEA-WEEDS. 



tinuous, transparent sheath. Eructification, purple zoo- 

 spores, one of which is formed in each cell of the frond. — 

 Bangia, named in honour of Hoffman Bang, a Danish 

 botanist. 



Some of the species of this genus are marine, some 

 flnviatile, and others grow indifferently in either salt or 

 fresh water. In this respect, as well as in the tubular form 

 of their fronds, they resemble the Enter omorpJuB, from 

 which they differ in colour. It would, indeed, appear that 

 the purple, tubular Banyia bears the same relation to 

 the purple, flat Porphyra, that the green, tubular Entero- 

 morpha does to the green, flat Ulva. 



Bangia fasco-purpurea. The brown-purple 

 Bangia. 



Fronds from two to three inches long, slender, simple, 

 straight, growing in decumbent, silky masses, which float 

 freely in the water, of a dark purple colour. 



This species grows on rocks or submerged wood, in 

 salt or fresh water. Its characters vary a good deal, 

 according to the age of the specimens. It is an inter- 

 esting object under the microscope. 



Bangia ciliaris. The fringe-like Bangia. 



Fronds parasitic on Algae, very minute, " scarcely the 

 tenth of an inch long." 



Writing of this plant in his ' Nereis B or eali- Ameri- 

 cana,' Dr. Harvey says, " Possibly it may be only the 

 very young state of B. fusco-purpurea ; but the habitat 

 is different, and the colour much brighter." 



