With 2 text illustrdtions.
Of recent years a new mode of thought has been more and more introduced into lirnnology. I t is foundedupon the p r o d u c t i o n -b i o l o g i c a l (83, 147-148)p r i n c i p l e s of R e g i o n a l L i m n o l o g y (91, 38). This regional lirnnology was first more closely understood as a result of extensive investigations of Swedish waters (31, 981, being then however further extended in range in several countries, notably those of Xorthern and Eastern Europe. OII the basis of the present literature a summary of the scope and principal problems of regional limnology will here be given to elucidate the present position of this new line of inquiry, to which a few suggestions for its further advancement will then be added'). There is evidence that interest in the regional aspect of limnological studies is everywhere increasing. The literature is however very dispersed and -like the practical objects in general of regional limnology -far from perspicuous to others than experts in just this field. And yet the problems of regional limnology must surely be regarded as belonging to the most ,,general" presented by present-day limnology. I have therefore thought that an English version of the original article might also be of use to the readers of this 'ournal.Thi contribution differs from the first in kaving a considerably augmented collection of the literature, which here comprises 194 works (as against 84 works). The list does not of course contain e x c l u s i v e l y such literature as can be classed under Regional Limnology in the modern sense. Many early and comprehensive works -some obviously forerunners of the regional limnology of our dayshave been included. The selection of the earlier literature must necessarily be somewhat conditional and cannot in any way lay claim to completeness. On the other hand, I venture to hope that I have gathered as complete a collection as possible of the more recent literature dealing with the more direct regional questions.To achieve this end has been one of my chief aims in the compilation of this article.
