156 INTRODUCTION TO CRYPTOGAMIC BOTANY. 



surmounted by a long hair-like point. Endochrome apparently 

 impregnated by bodies produced in little antheridia seated 

 on the walls of the fertile cells, dividing at length into four 

 ovate zoospores. 



J 29. This section consists of a single genus only, unless 

 Coleochcete should prove closely allied, containing three or 

 four species ; of which one occurs in Cayenne. It is usually 

 associated with Gluetopliora. The ramification of the threads 

 is not unlike that of some Cladophora, but a certain number 

 of the cells in the lateral branchlets end in a very long 

 colourless hair, while the base assumes the form of a little 

 bulb. The endochrome of this bulb soon becomes compact, and 

 at the same time little processes, like those of (Edogonium, 

 are developed on the surface (Fig. 26 6), and the wall itself 

 becomes fissured, apparently to admit the contents of the 

 microgonidia. The endochromes then acquire a membrane, 

 and appear to be perfect spores. After a rest, however, of 

 many weeks, the endochrome elongates and is divided into 

 four ovate zoospores, with a tuft of cilia at one extremity. The 

 species grow in fresh water, and one discovered by Mr. Thwaites 

 is a parasite upon one of the larger species. They appear, as 

 far as is known at present, to be confined to the northern 

 hemisphere ; they are evidently allied to (Edogonium, but 

 their habit, the formation and metamorphosis of their spores, 

 and other points, indicate their separation. 



11. Siphoned, Orev. 



Threads rooting, consisting of a single cell, often much 

 branched, and sometimes traversed by filiform processes, arising 

 from the walls, free or invested with calcareous matter. Pro- 

 pagation by minute zoospores, by large quiescent spores, or by 

 large active spores clothed with cilia. 



130. This tribe might be divided conveniently into several 

 sections, but the forms which it comprises are so closely 

 united, that it seems better not to divide too nicely. The 

 essential characters consist in the plant, however complicated, 

 being composed of a single cell, only variously modified. 



131. The most simple forms are displayed by those minute 

 Algae, more or less resembling microgonidia, which have been 



