Fresh-water Algae, of Canada. 345 



figures, and of a diameter that varies from a point to an inch." 

 In our specimens the globose frond is sometimes solitary, and 

 sometimes grouped in masses five or six together, and of various 

 sizes. It is of a deep green colour and very solid, requiring con- 

 siderable pressure to prepare it for the microscope. The internal 

 filaments are very prolifically branched, and from the apices of 

 the ultimate ramuli mucous setigerous threads protrude beyond 

 the gelatinous matrix. In this last particular, as well as in its 

 greater density, it is readily distinguished from Ch. tuberculosa. 



One curious fact is well ascertained in regard to many of these 

 plants, namely ; that there is a double process of development into 

 maturity : one of the primary spores into several individuals, and 

 another of the individuals by subdision into fronds. The spores are 

 sometimes parted twice, thrice, and four times, by the constriction 

 of their hyaline integument. By this means it is obvious that a 

 single plant, with its numerous cells and countless spores, will re- 

 produce itself at an immense ratio. Provision is thus made by 

 the Creator against the injury and destruction to which these tiny 

 germs are exposed, to ensure the perpetuation of their species, and 

 to maintain the progressive chain of creation. 



Another curious feature, especially found in the families now 

 described, is their power of secreting large quantities of Gelatine. 

 The mucous of the Chcetophora is greatly disproportioned to the 

 organised filaments of which it is composed. Whatever function 

 of nutriment this substance may possess, it unquestionally serves 

 the purpose of protecting the plant from injury — presenting no 

 points of resistance to the running water, or to the smaller bodies 

 which are carried along in its course. This mucous answers also 

 as food for aquatic insects, and for the smaller fishes. Dr. Living- 

 stone in his " Travels " mentions a fish in the Zambese River of 

 Central Africa, which feeds on a mossy kind of substance which 

 grows in the bottom of the river. Now we have no doubt that 

 this mossy substance is our Gelatinous Chcetophora. These there- 

 fore are some of the important uses which the mucous so largely 

 secreted by these plants serves in the economy of nature. 



(To be continued.) 



