78 Proceedings 
with such things we shall want information about the food af- 
fected by the different species; for our gardening friends are by 
no means right in assuming that all snails and slugs invariably 
eat everything that they ought to leave uneaten. 
Mr. W. A. Gain has made many experiments bearing on this 
point. I believe that a better method still remains to be tried; 
the examination of the contents of the snails’ stomachs. It is a 
regrettable fact, but snails must be killed in order that their shells 
may figure in collections; and the body, which contains the 
precious radula and various other points of interest, is generally 
not utilised. It should be very little trouble to examine the con- 
tents of the stomach under the microscope, when an experienced 
botanist, well acquainted with our native flora, would be able 
to recognise the remains of the tissues of different plants. 
The study of the radula also forces us to make further de- 
velopements. It is a very much more complicated organ than has 
generally been supposed, consisting of many other elements be- 
sides those rows of hooks and the membrane that bears them. 
We naturally ask how it has grown to that particular pattern; 
whether there is any important variation of its form in earlier 
stages. There is; and in the earlier stages the radula often shows 
close similarity to that of some other form; thus providing an 
interesting confirmation of Hyatt’s observations described by the 
President of the Malacological Society in his annual address this 
year. Hyatt showed, 20 years ago, that certain species never 
grew up to full maturity; many of course reached the maximum 
of age that was proper for the group, while others habitually at- 
tained what we may call the senile condition. He recognised 
that this fact could be put to good account in classification; and 
he named the stages of growth and decline by using suitable 
Greek adjectives: Embryonic, Nepionic, Neanic, Ephebic and 
Gerontic. He himself worked mainly at the Cephalopoda; but 
his observation is, I believe, destined to provide a key to the 
classification of that extremely complicated family the Helicidae, 
more especially when we take into account not the shells only, . 
but also the radulae and maxillae. 
To form a just idea of the nature of the radula, we shall re- 
quire to explore much mere deeply into its embryology. This 
