582 DR. J. B. HICKS ON THE GONIDIA AND 



of the cells. Every terminal cell seemed ready to separate, or had already done so. Each 

 was divided by a septum into two portions ; after separation, the cells began to increase, 

 and the contents became darker, more homogeneous, and ultimately they possessed the 

 appearance of a Chlorococcus, and rmderwent subdivision. 



Retrospect. — In reviewing the points of interest contained in the foregoiag communica- 

 tion, I shall take them in the order in which they have been presented. And the first 

 which seems to stand most prominent is, 



1. The peculiar tendency of the confervoid filaments to grow for any indefinite period 

 and extent in the same form and state, both in and out of water ; so that it is not to be 

 wondered at that they should have been considered independent vegetations. This 

 opinion appears still more excusable when it is considered that they can reproduce them- 

 selves by any one of their cells, which sometimes, becoming free and globular, presents the 

 appearance of a spore. How much more would it have been justified had the knowledge 

 of their segmentation, &c., been then possessed? It gives another instance of the im- 

 portance of the study of the entire life-history of all forms. We are much indebted to 

 Kiitzing (whose studies have had generally an opposite tendency) for first pointing out 

 the true nature and origin of these so-called Algse. 



At the same time, may I not ask, does it not make us question the origin of many of 

 the Confervoids, the tracing of whose whole history we have never achieved, of whose 

 sexual life we have no knowledge ? Of how many do we know only the vegetative 

 growth, with its formation of active (zoospores) gonidia and passive gonidia ! Let us 

 not conclude these to be finally placed, but let us follow them through by every possible 

 way, in order to detect all their phases of existence. 



The remark of Braun applies to this subject, as well as to those which follow : — " The 

 o-reatest care is requisite in their determination as independent organisms ; nor should 

 this be decided unless every stage of their evolution, from beginning to end, is known" *. 

 I can only add, When are we to know when we have found both or either ? 



2. The second thought which seems worthy of detention arises from the circumstance 

 that, out of these confervoid filaments, two or three genera with numerous species of Algse 

 have been founded. Frotonema, Oongrosira, and certainly some forms of Chroolepns are not 

 AlgaB, but the varying forms of these Moss-productions. We might well feel our faith 

 in specific and even generic distinctions in general staggered by these and similar facts, 

 l)ut more particularly in respect to the Confervoidese. We are bound to suspend our im- 

 plicit trust in the certainty of their position, at least as to many whose history is as yet 

 undetermined. It might be brought forward as an apology, that these forms were really 

 distinct, each kind belonging to separate Mosses. In answer, I might say that a few 

 observations would readily show that this excuse could not be sustained ; for I have 

 reason to believe that nearly all the varieties can be produced from each one of the 

 Mosses, if placed under varying conditions. 



The different forms of the confervoid filament, as I have already shown, depend on 

 external circumstances, rather than on the species to which they belong, although it 

 is possible that some exceptions may be found to this rule. The value of the distinctive 



* Braun, on Unicellular Algse, Mic. Joum., vol. v. p. 91. 



