118 Royal Irish Academy, 



Braiin, of Nageli and Pringsheim, are but a few of those whose 

 labours should well deserve to be recorded ; some of whom still remain 

 labourers in the field of biological science actively augmenting the 

 growing importance of their studies. The peculiar nature of those 

 beings which form, for the most pait, the objects of their inquiries 

 facilitates their investigations. "Wherever the foot of man can tread, 

 those minute and simple beings are to be met with ; no costly expedi- 

 tions are needed to collect them ; each, sea, and every land, affords their 

 special forms ; the upland lake, the marshy pool, the air itself, affords 

 fruitful material for inquiry. In our own country such localities 

 abound, but until lately this branch of biological science did not ap- 

 pear to attract much notice when Mr. Archer showed that our fresh- 

 water ponds possessed representatives of diverse types, some of exqui- 

 site beauty, and kindred with even tropical forms. 



Since that time our esteemed colleague has devoted himself, with 

 a patient assiduity and a microscopic tact which is beyond praise, to 

 this class of researches, and his spirit of inquiry and honest love of 

 truth has afforded him an abundant harvest of important and interest- 

 ing results, to a few of which I shall very briefly direct attention. In 

 1855, Mr. Archer laid before the Zoological and Botanical Association 

 of the University of Dublin a Catalogue of the Desmidiese of the 

 County of Dublin. This was followed up in the ensuing spring by 

 a supplemental list. Modestly styled a Catalogue, these two memoirs 

 constituted excellent original essays on the species forming that group ; 

 giving descriptions of new genera and species, illustrated by drawings 

 from the author's hand. By this publication Mr. Archer took at once 

 a high place among original investigators ; and when the long illness 

 of Mr. Ralfs prevented him from revisirg the new edition of the 

 Desmidieas for Pritchard's well-known work on the Infusoria, the task 

 was committed to Mr. Archer's care. Since that time a long series 

 of Papers on these subjects has flowed from his pen, so that now, in 

 every work relating to that class of organisms, one finds our col- 

 league's name and labours referred to as an authority. I need not 

 detain you with a long list of those Papers, contenting myself with 

 the statement that by them our knowledge of the unicellular and fila- 

 mentous algse has been largely increased. 



The close relation between the two kingdoms of organic nature, 

 especially in their lowest and more elemental forms, necessarily leads 



