10 LAND AND FRESH-WATER SHELLS. 



abode. The rules are what I term "golden rules;" i.e., rules 

 not to be forgotten ; but the one rule of the assiduous collector is 

 to search in every crink and cranny, and never to pass over a 

 spot without a full examination of its whole surface. The imple- 

 ments needed for this collecting are few in number and inexpen- 

 sive. Two of them are given you by nature nimble fingers and 

 quick eyes ; one forms a companion in your walks, the walking- 

 stick ; the others, which will have to be purchased, are a dredge, 

 a scoop, or a water-net, and a few chip boxes. The walking-stick 

 will be useful for pulling water-weeds to the bankside, so that 

 they may be easily examined with the fingers for specimens. The 

 dredge will be needed for the collection of Unios, Anodons, 

 Sphczria, and Pisidia, which, being bivalves, live almost entirely 

 on the bed of the pond or stream. This can be made after the 

 following figure of a net-dredge recommended in Messrs. Gray 



Fig. 2. A Water-dredge (Woodward). 



and Woodward's companion volume, " Seaweeds, Shells, and 

 Fossils ; " but my preference is to having a properly weighted 

 square frame rather than a circular one, as it takes a larger area 

 of the water-bed at the same time, and, consequently, is more apt 

 to work up a larger number of specimens. The scoop is not in 

 general use, I think, but, nevertheless, it is an exceedingly good 

 implement to use for sweeping among water-weeds which cannot 

 be brought to the bankside with the stick, and perhaps is more 

 welcome and more serviceable than the ordinary water- net, for 

 which it forms a substitute. Mr. Wallis Kew and I have taken 

 a large number of specimens with it from the Tottenham Marshes, 

 by the way, a happy hunting ground for the London collector. 

 Mr. Denison Roebuck has his made of copper, but zinc will be 

 found cheaper and nearly as serviceable a material. A circular 

 ring of zinc is made, of about an inch and a quarter in depth, 

 and of about eight inches in diameter. A perforated zinc bottom 



