12 NATURAL HISTORY SOCIETY OF DUBLIN. 



JANUARY 9, 18G3. 



Bobert Callwell, Esq., M. B. I. A., V. P., in the Chair. 



The Minutes of the preceding meeting having been read and con- 

 firmed, 



The following paper was read : — 



An Endeavour to identify Palmoglosa Macrococca (Kutz.) with 

 Description of the Plant believed to be meant, and of a new 

 Species, both, however, referrible rather to the Genus Meso- 

 t^nium (Nag.). By "William Archer. 



"What is Palmoglcea macrococca (Kutz.) ? Is the plant to which to- 

 night I draw attention, that so named by Kiitzing ? It is a privilege 

 frequently conceded to, or at least often claimed by an Irishman, to be 

 permitted to answer one question by asking another. It is, however, 

 one of which I do not just now seek to avail myself; but, before endea- 

 vouring to answer the question, as to what plant I conceive it highly 

 probable Palmoglcea macrococca (Kutz.) really is, I may be permitted 

 by and by previously to draw attention to one or two related plants, 

 which I believe it is not, and which may have been mistaken for it, and 

 for each other, but none of which, as I imagine, are really the actual 

 form so named by Kiitzing ; and this latter point, if correctly ascertained, 

 is at least a step towards the end in view, and serves to narrow the 

 range of subsequent inquiry as to identity of species. As to any more 

 or less restricted or comprehensive application of the latter word, I shall 

 not venture to enter into any disquisition here. The plants or their 

 near allies immediately under consideration are at least forms which, 

 so far as Professor DeBary's beautiful observations go,* reproduce their 

 like by a conjugative act, and, certainly, maintaining their specialities 

 and characteristics, are with greater or less frequency met with by those 

 who seek for them in their own habitats. 



I have just alluded to the plants which more particularly form our 

 present subject— the species of Mesotsenium (Nag.) — as possessing pro- 

 per specialities and characteristics. Such an assumption, in regard to 

 forms of so simple structure — unicellular plants destitute of a figured 

 outline, and of any great external variety of form, and, I need not add, 

 of anything like special external organs, and possessing so much in com- 

 mon with each other — may seem to some untenable. It is indeed to 

 be conceded, that for the reason just mentioned, their distinctions are 

 very difficult to express by description, and hardly less so by figures ; 

 but I do think that a careful examination and comparison of the living 

 examples must convince any one of their actual specific diversity, 



* " Untersuchungen iiber die Familie der Conjugaten," pp. 34, 37, t. vii. 



