l8 NATURAL SCIENCE. January 



working towards this end. And these problems are, for the most part, 

 not the narrower specialist questions, but those of great general im- 

 portance bearing on vexed points of variation, heredity, selection, and 

 the influence of environment. 



As to the position of such a British station, it would probably be 

 well, for reasons of accessibility, to limit the possible situation to 

 England and Wales, although the claims of several locahties in Scotland 

 and Ireland are not light. Undoubtedly the three districts in England 

 and Wales offering most suitable conditions for the establishment of 

 a fresh-water station, are the Lake District, North Wales, and the 

 Norfolk Broads. The claims of the Lake District and North Wales 

 are very much of the same character, though probably the former has 

 a somewhat richer aquatic fauna and flora than the latter. In both 

 cases some of the principal work to be done would be carried out upon 

 the free-swimming organisms constituting the fresh-water "plankton." 

 That the detailed study of these forms is likely to lead to important 

 results may be seen from the ['following considerations. The number 

 of species constituting the bulk of the plankton of fresh-water lakes is 

 remarkably small, the conditions of existence are comparatively simple 

 and uniform, and the certainty with which typical collections may be 

 made is at its maximum. In fact, in studying the fresh-water plankton 

 one gets, under perfectly natural conditions, almost the simplicity of 

 an artificial experiment, and it is here, if anywhere, that some of the 

 problems of selection, variation, and heredity will find a satisfactory 

 solution. Many other lines of work besides observations on the 

 plankton could easily be undertaken by a station in either of the two 

 districts named, but the latter would still form its characteristic 

 feature. The Norfolk Broads and rivers, on the other hand, offer Httle 

 opportunity for plankton work, but possess the unique character of 

 presenting continuous and nearly imperceptible gradations from 

 absolutely fresh to brackish, and even salt water. This is a condition, 

 the influence of which has never been sufficiently studied, and has 

 certainly never been touched by any existing biological station. 

 That this peculiarly favourable example of gradation from fresh to 

 salt water is leading to important changes in the habits of various 

 species is almost certain, and it has already been shown for one 

 group of animals, viz., the Ostracoda (see Brady and Norman's 

 Monograph of the Ostracoda, &c., Royal Dublin Society's Transactions, 

 1889 and 1896), that several species, which are typically brackish 

 {Cypridopsis aciileata, Cythere pellucida, C.fuscata, &c.), are now living in 

 broads and dykes that are quite fresh, whilst other forms, essentially 

 marine {Cythere antiquata, Loxoconcha guttata, &c.), have succeeded in 

 pushing their way into the brackish waters of the district. These 

 facts suggest a subject for systematic observation which should be 

 taken up by a biological station on the Norfolk Broads as one of 

 its most important duties. It is certainly not too much to hope that 

 in this way some very important additions to our knowledge of the 



