47 



to show in each case the locality of capture, the authority for it, and (where practicable) the 

 depth and temperature. 



The positions have all been reduced to the meridian of Greenwich, if expressed as 

 latitude and longitude. Those positions which are enclosed in square brackets [ 1 were not 

 given in that form by the original authority, but have been roughly measured off on charts 

 and maps, or deduced in some other way; they are not likely to be correct to within a few 

 minutes, but then neither a Chaetognath nor an isotherm can usually be fixed with a oreater 

 accuracy. For some not very obvious reason, the positions published by Hensen for the 'National' 

 were- expressed in tenths of a degree instead of in minutes; for these the day's position has 

 sometimes been got from another part of the reports, in other cases the tenths have been 

 multiplied out into minutes, and enclosed in square brackets. 



The authority for the record will be found in full in the List of Literature below, 

 the number following the author's name indicating the date of publication. 



The depths are only thoroughly satisfactory in the case of closing nets. As open Vertical 

 Nets are absolutely valueless for deciding the maximum depth-distribution of an epiplanktonic 

 species, it seemed useless labour in most cases to reprint the depth to which such nets were 

 lowered. And if such data of depth are valueless, the corresponding temperatures also can 

 have little significance ; it is of no great interest to know that an animal was livino- at a 

 temperature somewhere between 8° and 27 ; the limits are too far apart. 



But since, if sufficiently numerous, Vertical Nets do yield some indication of the minimum 

 depth-distribution of a mesoplanktonic l ) form, in such cases the depth to which they were 

 lowered has been recorded where practicable. 



All depths have been reduced to metres. 



The temperatures have all been reduced to the Centigrade scale. Where they were 

 not recorded by the original authority, they have been enclosed in square brackets; in such 

 cases they have generally either been interpolated on curves, the data for which were to be 

 found in the original publication, or are Mean Annual Temperatures [M. A.] for the position 

 and depth, gathered from Schott c ), Mohn 3 ), and Koppen *). 



When two temperatures are given (for example, o° 3 to 3 1 ) it is not necessarily 

 implied that the species was found actually at either, but that they are the extreme possible 

 temperatures of that particular capture. 



Since the temperature of the water of the Eastern coasts of Japan is stated to vary 

 greatly with the time of year, the mean annual of Misaki, from the harbour of which a large 

 number of species have been recorded, is probably a rather vague approximation. 



1) At a given position the epiplankton is understood to include the plankton down to about ioo fathoms (182 m.), the 

 mesoplankton to extend from about that level to within about 100 fathoms or less of the bottom. But no sharp line is implied between 

 them, and Chaetognaths have been described as coming to within about 91 m. of the surface, without apparently coming actually to it 

 at that particular position. 



2) G. Schott, Ergebn. der deutschen Tiefsee Expedition a. d. Dampfer Valdivia 1898 — 1S99. Band I, Oceanographie und 

 maritime Meteorologie. Jena, 1902. 4to. 



3) H. Mohn, Den Norske Nordhavs Expedition. Meteorologi. Christiania, 1883. 4to. 



4) Deutsche Seewarte : Stiller Ozean. Atlas. Hamburg, 1896, Fo. 



