262 NATURAL HISTORY SOCIETY OF DUBLIN. 



opportunity to bring before your notice the Irish forms of that genus ; 

 or rather, those forms which by Kiitzing would have been referred to 

 it, but which, as I then stated, and as I still apprehend, belong more 

 naturally to several individually distinct but closely related genera. I 

 gave at the same time what may be called, in some measure, an ana- 

 lysis of the genus Palmoglcea (Kiitz.), with regard to at least the majo- 

 rity of the forms therein included by that algologist. 



Dr. Hicks does that communication the honour of a special paper, 

 in which he expatiates at some length on the validity of the characters 

 which may seem available for the classification of the " unicellular" 

 Algae, and in doing so he touches upon some of the points alluded to 

 by me.* This able observer has had large experience amongst those 

 humble forms ; and I have always perused his communications with all 

 the attention to which they are so eminently entitled, and with all the 

 interest they are always so well calculated to excite, as well as with 

 all the gratification their richness in novel information is sure to 

 impart. 



The paper in which Dr. Hicks does my previous one the honour of 

 a notice aboands with observations full of importance, and in it he pro- 

 pounds many pertinent queries. As he, however, differs with me in 

 some of the opinions put forward in my paper, which indeed I do not 

 yet see reason to change, and as I am, on the other hand, quite dis- 

 posed to agree in a great measure with him on certain other points put 

 forward by him, though not referred to by me in my previous paper, 

 I may perhaps be allowed again to offer a few observations on the 

 subject. 



But I must in limine contend, inasmuch as my paper was not on 

 Palmellacese in general, but on the genas Palmoglcea (Kiitz.) in parti- 

 cular, that much of the reasoning and many of the questions pro- 

 pounded by Dr. Hicks do not therefore apply to, nor do they, I think, 

 at all controvert, my therein expressed views. And it is for this reason 

 that I say I venture in some points to disagree from, and in others to 

 agree with, Dr. Hicks ; for if we conceive Palmoglcea (Kiitz.), or, more 

 properly speaking, the three genera, Cylindrocystis (M eneghini), Me- 

 sotaenium (Nag.), and Spirotsenia (Breb.), which indeed were the 

 actual subjects of my paper, to be eliminated from the question, I 

 think I must in a measure acquiesce in his views, though without at 

 all consenting as yet to accept them in the aggregate. 



Dr. Hicks puts forward the title of my paper — "An ^Endeavour to 

 identify Palmoglcea macrococca (Kiitz.)" — as, in itself, some argument for 

 the want of stability in the Palmoglcean species. Considering this un- 

 certainty as regards these forms as unquestionable, he would from 

 them, as a starting point, argue as regards Palmellacese generally. It 

 is true that he attacks the independence of many of that family else- 



Quarterly Journal of Microscopical Science," N. S., vol. xii., p. 253. 



