Report on the Irish Diatomaceae. Part 1

Abstract

on the Irish Diatomracet. 235 XXXVII.-REProuT oN tT ITsH DiATOm&CEJE. By the REv. EuGeNu O'MEA, M. A. Part I. (With Plates 26 to 35.) [Read June 28, 1876.] It is; now just a century, since in 1773, 0. F. Mler discovered the first known diatomaceous form; nor was: it till ten years after, the ame distinguished author was able to add two new forms to the list. In the year 1824 Agardh published his "Systema Algarum;" and then the number of species was forty-nine, comprehended under eight genera. But if in this province of Natural Science the progress was slow during the first half century, it has been very rapid in the last, Qwing not only to the number of eminent labourers in this field of research, but also to the greatly improved means of investigation. The number of species in Europe alone, as computed by Rabenhorat in his index, is about 4000. This may be beyond the mark, but certainly Pfitzer is far short of it when he fixes the total number of known species at about 1000. It is not necessary to enumerate the many authors to whose useful labours the students of this branch of Science are indebted,-but special notice should be made of Kitzing, who explored the whole surface of the globe; and of Ehrenberg, who, not content with the same ample field of investigation, extended his researches into the bowels of the earth. But no authors, perhaps, have contributed so much to the extent and accuracy of our know ledge, as those who have restricted their labours to some special families, or to the collection and examination of the forms incidental to some country or district. The treatise on the Diatomaceae of the Clyde has earned for Gregory an imperishable name. The Austrian forms have been described by Grunow. The Prussian by Schuman. The Danish by Heiberg. Those of Sweden and Norway by Cleve, and those of Great Britain by Smith in his admirable Synopsis. No country would appear more favourable to the growth of these forms than oulr own, with its extensive sea-coast indented with numerous bays, its rivers and lakes, and mountain ranges. And yet it is strange that Smith, an Irishman, at least labouring professionally inL Ireland, should have done but little in exploring its resources, as appears from the fact that, in the case of 389 forms figured and described by him as British, there are not more than about one hundred for which Irish localities have been assigned. Hence it might be supposed that the climate of Ireland is not favourable to the growth of Diatomaceous forms,-an impression which is not justified by the fact, as I hope to prove b the present work. For many ye ar the intervals Of professional engagements had been devoted by me to the collection and study of the Irish Diatomacet; and a large amount of material had been gathered and arranged when X,. I. A. PROC., SEE. M., VOL. II., scrxci. 2 x