FRESH WATER 189 



certain conditions must be observed, (i) It is necessary to have 

 a long stick the longer the better to the end of which there 

 may be attached various kinds of net (like small butterfly nets) 

 and collecting jar. The pupils can often do much with a tin 

 dipper on the end of a stick, but some ponds are so dangerous 

 that the collecting must be left to two or three careful seniors. 

 (2) It is necessary to have two kinds of receiving vessel into 

 which to place the animals collected, shallow vessels like soup 

 plates to be looked down into, and tall glass vessels with flat 

 sides to be looked through. It is almost as easy to carry half a 

 dozen white soup plates as one, and by distributing these among 

 the pupils careful observing with lenses may be facilitated. A 

 large milk-basin to serve as a temporary aquarium to hold larger 

 specimens, such as small fishes, is also useful. (3) It is necessary to 

 take from the pond different kinds of samples surface skimmings 

 and mud from the bottom, water weeds of various kinds, stones 

 from near the edge, floating pieces of wood to put these separately 

 into the plates, and to watch what appears in the various cases. 

 It is important that the young observers should get into the 

 habit of watching till what is collected settles down, and what 

 was not at first obvious begins to appear. (4) In the case of 

 some ponds with clear water and suitable slope it is possible to 

 sit down or lie down on the bank and simply watch what is going 

 on beneath the surface. But one cannot trust to this, for a little 

 wind makes a surface-ripple that dims everything, or the water 

 may be cloudy, or all the animals may be in hiding. (5) As in 

 the cases of other haunts, the general advice may be given to pay 

 the haunt a visit at different times of day and at different seasons 

 of the year, and not to try too much at once. We restrict our 

 hints to noting a dozen things or sets of things that should be 

 looked for and studied on a first visit to a pond. 



Water-Vole and Water-Shrew. On the banks of the pond 

 or mill-dam, a.s also of streams and canals, the water-vole 

 (Microtus amphibius) usually miscalled the water-rat makes 

 its long twisted burrows. It can be distinguished from the 

 brown rat (Mus decumanus\ which is of about the same 

 size, and may occur in the same sort of place, by its much 

 shorter ears (hidden among the fur), by its relatively shorter 



