Ix THE BEGINNINGS OF IIFE. 



the branching of the thread is not sufficient, or the mode 

 of branching. Cladophora glomerata assumes a multitude of 

 forms which it would be rash in the extreme to separate, 

 and it may be safely affirmed that of published species of 

 Cladophora and Conferva^ at least one-half will ultimately 

 be reduced. Where ConfervcE are exposed to drought, they 

 sometimes throw down roots from their joints in search of 

 moisture, a circumstance which must be taken into account 

 in the estimation of species. In Lynghya miiralis the threads 

 often anastomose, producing a very curious and puzzling 

 appearance. ... In Anabaina and allied genera, the number 

 and disposition of the fertile cells will not afford safe cha- 

 racters ; nor will mere microscopic measurement, which is 

 often deceptive, and should be always taken with consider- 

 able latitude amongst OscillaioricB. The zoospores even of 

 the articulated Algae are not absolutely constant. Monstrous 

 forms occur in the small zoospores of Cladophora, and the 

 large ones of ^dogonium. Characters like those in Hassal's 

 Fresh Water Algae, dependent simply on comparative size, 

 are altogether inadmissible, as specific distinctions.' 



From a study of some of the OscillatoricB, and more 

 especially of Lyngbya muralis, Dr. Hicks ^ has not only 

 ascertained that these plants take on many distinctly differ- 

 ent modes of growth from time to time, but that they also 

 frequently throw off some of their terminal cells in the form 

 of gonidia, which straightway proceed to undergo a process 

 of segmentation after the fashion of the gonidia of Lichens, 

 so as to produce a palmelloid growth, which frequently 

 assumes the form of Protococcus viridis. Some of the cells 

 of these, after a time, may again take on the linear mode 

 of growth, and so revert to the original Lyngbya type. At 

 other times, by the occurrence of a lateral mode of segmen- 



^ 'Journ. of Microsc. Science,' 1861, p. 157. 



