20 Our British Snails 



then it is well to wash out any slime or particles 

 by directing a fine but strong jet of cold water 

 into the shell. This can be done by holding 

 your thumb nearly over the mouth of a water- 

 tap, while the shell is held in the left hand. Only 

 adult shells should usually be taken, and those 

 which are weather-worn or bleached should be 

 neglected. In most the lip, or opening, of the 

 shell will be hard if adult, and membranous if 

 young ; but experience alone will enable you 

 to discriminate, especially where the young of 

 one species is like the adult of another. 



Get into the way of carrying a note-book 

 with you to record not only what shells, or 

 varieties of a species, are found in any particular 

 spot, but also anything you observe as to the 

 habits or peculiarities of the objects of your 

 search. Notes as to protective colouring or 

 mimicry ; the influences of a wet or a dry season 

 on the relative thickness of shells ; the difference 

 in size caused by abundance or scarcity of diet ; 

 what plants are preferred and what avoided 

 as food by particular helices, — are some of the 

 points of interest, apart from the earliest and 

 latest dates at which certain species are abroad 

 and active. 



If you possess, or borrow, a microscope, many 

 new wonders and fresh lines of inquiry will 

 open out. I know one professor who devotes 

 himself to the study of the teeth of molluscs. 



