32 The Irish Naturalist. March, 1924. 



of marine fishes and faciUtate future fishery legislation. This body of 



experts is known as the " Permanent International Council for the 



Exploration of the Sea." 



The discussions and results of their researches are published in a 



series of valuable reports. During the war the issue of these reports 



was naturally much restricted, but it is intended now to resum.e the 



work with renewed vigour. 



Just before the outbreak of the war a paper of considerable interest 



to Irish fisheries was issued in what are called " PubUcations de Circon- 



stance." It was written by a Swedish naturalist, Mr. David Nilsson, 



and dealt with the biology of the Mackerel. Although the investigations 



were carried out in Swedish waters, where the ]\lackerels seems to differ 



slightly from the Irish form, the results obtained will be of considerable 



value to anyone undertaking an intensive study of the Mackerel in Irish 



waters. The length and weight of the fish, its mode of growth, food, 



its parasites, sex, maturity, its eggs and larvae, as well as its variation, 



are noted and commented upon at length. 



In the same series Dr. C. H. Ostenfeld published in 1916 a valuable 



catalogue of the various species of microscopic plants and animals 



observed in the plankton gathered between the months of July, 1908, 



and December, 191 1. Together with the two catalogues issued in 



previous years this latest list furnishes us with a survey of the plankton ic 



organisms in the seas within the purview of the International Council 



during the period of 1902-1911. As a good mainy references to Irisli 



localities are given the catalogue will be useful to Irish naturalists 



interested in the microscopic forms of marine life. 



Finally, in J920. Mr. G. P. Farran published a paper " On the local 



and seasonal Distribution of the pelagic Copepoda of the South-west of 



Ireland." The author includes important observations upon salinity 



and temperature of the water both of which affect the distribution of these 



most valuable minute crustaceans. The lattec, constituting one of the 



principal foods of young fishes, naturally affect and influence the migration 



of fishes. The total number of species taken during the period under 



consideration seems to be large, and yet the ninety species recorded by 



Mr, Farran only constitute a part of the microscopic copepoda occurring 



in this area. He acknowledges that the meshes of the net used allowed 



a very large proportion of the species to escape — in fact all those under 



I . 3 mill, in length. The species contained in the list are divided into 



four groups according to their mode of life. There are first the " n critic " 



or coast forms, secondly the " euryhaline " species or those whose 



abundance is not related to the salinity of the sea, then come the 



" oceanic " species, that is to say, those most abundant on the station 



or localities remote from the coast, and finally the " benthic " forms 



which are those living at or near the bottom of the sea. Thus of the 



two economically the most valuable and also the most abundant species, 



Calanus finmarchiciis is described as being n critic, whereas JMctridia 



lucens is euryhaline. 



R. F. S. 



