INTRODUCTION. 



Fish. Reptiles. 



A section of the Diary is set apart for recording observations on fishes 

 and reptiles, and the names of our ordinary British varieties are given in 

 the general index. A few recorded observations are also introduced into 

 the pages of the Diary from Gilbert White's Diary to serve as centres for 

 further records, but these almost entirely refer to reptiles. 



The invention of fresh and sea-water aquaria has made the study of the 

 habits of fishes and similar organisms easy and popular, while the recent 

 Fisheries' Exhibition and the biological stations on our coasts have given 

 a great impetus to such investigations under natural conditions by natu- 

 ralists and fishermen. The migrations, spawning, and hibernatio n of 

 fishes, are periodic phenomena of the same character as those displayed 

 by other organisms, and should be studied side by side with them and 

 with the changes of the seasons and physical phenomena with which they 

 are associated. The culture and acclimatization of fishes in our rivers, 

 lakes, and ponds, is a subject of great scientific interest and economic 

 importance ; and though its practice is still limited in extent, it is one 

 which is simple and easy of application. 



Fish-hatching is carried on indoors, between the beginning of Decem- 

 ber and the end of March, by means of long narrow boxes (3 feet long, 

 7 inches wide, and y4- inches deep, fitted with a dark cover), the bottoms 

 of which are covered with half an inch of clean, roughish gravel, and over 

 which a gentle stream of cold clean water is kept constantly flowing. 

 The eggs, which can be purchased from regular dealers, after being 

 cleansed from moss and other packing, are spread out on the gravel (from 

 two to three thousand in a box of the above dimensions), and the cover 

 placed over them to protect them from the light. At this stage, Frank 

 Buckland's advice is " to do nothing at all," except remove the dead eggs 

 every morning by means of a glass tube or pipette. Live eggs are suffi- 

 ciently transparent for the eyes of the young fish to be just visible, and 

 the vibratory motion of the tail to be distinguished ; but dead eggs 

 become white and opaque, and can therefore be easily recognized. When 

 the young fish are hatched the stream of water must be increased, but 

 otherwise " let them alone.'^ The most important thing to attend to at 

 this stage is to keep the water cold (by the use of ice if necessary), say 

 down to 42° F., as warmth is very destructive to young fish ; and all dead 

 fish must be removed from the boxes. Some pieces of slate, under which 

 the young fish may take shelter from the light, should be placed in the 

 boxes. Later, when the bkg of food with which the young are provided 

 at their birth is about half absorbed, the fish must be fed with the roe 

 of soles (boiled and broken up), or, as Buckland recommends, on small 

 red mud-worms obtained from the bed of the Thames, and sold by Mr. 

 Newman, of 32, Thanet Street, W.C. In spring the fry must be turned 

 out in shallow streams, or further protected in " fish nurseries," until they 

 are large enough to be turned direct in to rivers and lakes. 



