//-£, 



i 



'^'"/-a/w the 

 ious and 



PUZzliB 



7 







?^^^era, the nunife 

 ^^ afford safe 4 

 ?urement, which is 

 ^en with consider- 

 zoospores even 

 .stant. Monstrous 

 'ladophora, and 

 e those in Harf 



comparative 



inctions. 



J 



^atoricE, and more 

 cs 1 has not odIj 



:v 



distinctly 



but that tliey ali' 



,1 cells in the foi» 



undergo 



of W 



a 



r 



onidia 

 some of * ■* 



the Ii«* " 



1 



r 



ode 



'a t}f • 



At 

 me"' 



I 



i 



APPENDIX D. 



Ixi 



tation, there are produced from the Lynghya thread broad 

 ;vavy fronds, the cells of which are held together by colour- 

 less intercellular substance. Such fronds may also throw 

 off gonidia, and these may go through all the changes above 

 described ; or some of its peripheral cells may take on the 

 linear mode of groAvth. Dr. Hicks says \—' The whole of 

 these changes are so palpable, can be observed so constantly, 

 and are, at the same time, so simple in their relations to 

 one another, that one can scarcely imagine how they can 

 have been separated, not only into distinct species, but into 

 different families of Algae, Thus the linear stage is called 

 Lynghya; the early stage of collateral segmentation, Schizo- 

 goniunt; the adult stage Prasiola^; while the gonidial growth 

 has been classed under Palmellace(2. And this has been 

 done by most algologists. Meyer, indeed, had pointed out 

 a connection between them; but his opinions were denied 

 by Jesseu, and ignored by most others. It is a striking 

 instance of the insuperable tendency of some to look upon 

 every distinct form as a separate species/ The characters 

 of the cells or segments in Lynghya are subject to changes 

 of all kinds, not only as regards the particular characters 

 of the green colouring matter contained in them, but also as 

 regards the shape and size of the segments. They may be 

 more or less rounded, so as to resemble those of Nostoc, 

 and their length not only varies much in adjacent filaments, 

 even occasionally in different portions of the same fila- 

 ment. This depends altogether 'upon the rapidity of the 

 process of linear subdivision, compared with the rapidity of 

 individual cell-growth. Sometimes the rate of the former 

 so much in excess, that the cells are no thicker than the 



but 



IS 



septa, the thread appearing to consist of narrow green and 



Ihe two latter genera have always been located in the family 



). 157- 



