2, LAND AND FRESHWATER 
I am most fortunate in having as a neighbour Mr, J. S. Gladstone, 
an excellent and skilful photographer. Without his valued aid 
I could not give the figures of types and shells from typical 
localities, which show far better than any description the direction 
their subtle differences take. For instance, how distinctly photo- 
graphy shows the difference between G. tenuispira of Teria Ghat 
(Plate CLIX. fig. 3) and the species for long regarded as the same 
trom Sikhim (Plate CLIX. figs. 1 & 2). Mr. Gladstone made 
photographs of 60 shells, which fill three Plates. I may say here, 
but for this generous assistance, the publication of this Monograph 
would not have been possible. As an example of Zoological 
Research it has been met, and by private means alone. 
Genus GLESSULA. 
Wuitez I have been studying this genus, particularly the animal, 
as specimens were slowly obtained in spirit, knowledge of its 
taxonomy has increased. ‘This has led me to look at many species 
very closely, for much had been left incomplete by Colonel Beddome, 
particularly the species from the North-Kast Frontier of India, of 
which I possessed a very fine series. 
Some of this work on the genus Glessula might have been 
published long ago in the second volume of the ‘ Fauna of British 
India’—some of it, anatomical, had been done ready for it; 
but I found 1 could not, under the conditions in which I was 
expected to work, complete it in time. [had reached an age when 
extra correspondence was to be avoided, when independent con- 
chological work was pleasanter to do. It was not to be expected 
I could place my collection at the service of others, neither could 
I hand over original work on the animals of the genus on which I 
had spent so much time and expense during many years. I 
could not give the public the run ef collections I had deposited 
in the Natural History Museum under certain well-defined and 
very reasonable conditions, reserving to myself the right to work 
on them during my lifetime. 
At the end of Vol. IL. (p. 485) I mentioned the genera I was 
engaged upon and trusted to deal with. Of these Glessula has 
been completed and is now presented in Part I. of this new 
volume. ‘The anatomy of several species has been made known, 
and, when working out the collections made when the punitive 
expedition entered the Abor country and the T’sanspu Valley 
(1911-12), I took the opportunity of publishing the anatomy of 
a new species from Sikhim to elucidate that of the genus, 
as I did not see at the time, with the war going on, any chance of 
publishing it at all. The animals of other genera have come 
to hand and have been described and figured in the following 
