400 Mr. TawMT^s on the early Stages of Development 



for a minute Conferva ; yet, notwithstanding, it bears the same relation merely 

 to the mature Lemanea that the confervoid shoots do to the perfect Moss, or 

 the mycelium to the fully- developed Agaric. 



Kiitzing in his ' Phycologia Generalis,' p. 322. tab. 19. fig. 10, has described 

 and figured the early condition of Lemanea torulosa, Ag. Except in the more 

 considerable development of the primordial confervoid filaments of the Le- 

 manea Jluviatilis, there is little difference in the mode of growth of the two 

 species. 



From a cell near the base of the conferva-like structure a branch is given 

 off (Tab. XIX. fig. 8 a & i), which at first differs apparently from one of the 

 ordinary branches only in the cells of which it is composed being much 

 shorter. This little branch, however, increases very rapidly in length as well 

 as thickness from the multiplication of its cells by frequent fissiparous divi- 

 sion. At one period of its growth it recals to mind the silicle of an Ectocar- 

 pus ; but the similarity does not long continue, for it soon exceeds in height 

 by many times the conferva-like filaments ; and as this rapidity and excess of 

 development has called for a greater supply of nourishment and a firmer sup- 

 port than could be furnished by the filament from which it took its origin, a 

 number of roots have been given off from its own base (just as occurs in the 

 phyton of a Moss), by which it is enabled to assume an independent existence 

 (fig. 8 6 & c), and from this period it by degrees puts on the well-known 

 characters of the Lemanea frond, which it is quite unnecessary to describe 

 upon this occasion. 



The subject of the early stages of growth of the Algse opens a wide field 

 for investigation, which would doubtless repay the careful observer by the 

 discovery of many most interesting facts, valuable to the physiologist as well 

 as to the systematic botanist. It is highly probable that very many of the 

 structures now classed with the Palmellece are merely immature states of 

 more complicated species ; and there are perhaps many others of the same 

 character which we at present look upon as being in the condition of complete 

 maturity. For arriving at safe conclusions, however, in such investigations, a 

 good microscope and a practised eye are indispensably requisite, since without 

 such precautions, really essential characters in these minute forms easily 

 escape detection, and structures totally different come to be considered iden- 



