PALMELLACE.E, 87 



fronds, often several inches long, a few being fila- 

 mentous. They consist of one or more sheets or 

 layers of cells, containing mostly green endochrome. 

 This at first fills the cells, but subsequently becomes 

 converted into single spores, or subdivided into nume- 

 rous ciliated zoospores. 



Ul'va latissima is very common on the sea-coast, 

 being found attached to stones, shells, &c. It forms 

 a broad, flat, green, rounded or^oblong, thin frond, 

 wavy and crumpled at the margins, and from 6 to 

 18 inches in length. The minute cells form two 

 layers, adherent to each other. The zoospores formed 

 are numerous in each cell. 



Enteromorpha compres sa (PL IV. fig. 31) is also 

 common in the sea and in brackish ditches ; it is 

 often found floating. The frond is green, tubular, 

 flattened or compressed, and branched, the branches 

 being usually simple and narrowed at the base. The 

 frond consists of two layers of minute cells, separated 

 .by a space rendering it hollow. The zoospores are 

 numerous in the cells (fig. 32) . 



PALMELLA'CE^. These Algae are found in fresh or 

 salt water, or on damp earth, wood, &c. They are 

 green or red, forming round or irregular masses or 

 strata. They consist of loosely connected cells, im- 

 bedded in a gelatinous mass or matrix, thus forming 

 a frond. 



Chlorococcum vulgdre (PL II. fig.l) is very common 

 upon the bark of elm-trees, palings, &c., forming a 

 green granular crust. It consists of minute rounded 

 or oval cells, mostly undergoing division into twos, 

 fours, or eights. These cells are attached to the 

 sides or ends of very fine colourless filaments. It is 

 most probable that this organism, which is usually 

 placed among the Algae, consists of the gonidia of a 

 Lichen. 



Chlorococcum muror'um forms a somewhat similar 

 .but soft and thin green layer, upon damp walls or 



