10 LAND AND FRESHWATER 
as to the close relationship, especially shown in the genitalia. 
Diakia did not occur among the Abor collections, unless it shall 
eventually turn out that Bensonia(?) aborensis, Rec. Ind. Mus. 
vol. viii. p. 596 (text-fig. 1), has similar anatomy. Im shell 
character it is unlike that of any Indian Genus | have seen; but 
J had only one specimen to deal with. 
For a knowledge of the peculiar anatomy of Diakia, we have to 
go to Semper, where he deals with what was then known as 
Arivphanta rumphir in Reisen, pl. ii. fig. 18. 
rarequttata, Var. sparsa on on tig. leit 
nemorensis ee a edSsa ioe 
striata, Gray =naninordes, Bs. » fig. 21 a-b. 
He gives beautiful figures of the genitalia, so unlike those of any 
strictly Indian Genus. 
Our knowledge of the Assam Land Mollusca is very imperfect ; 
much has still to be done, with small chance of our knowing more 
under present conditions. In fact, discovery of species of great 
interest is sheer luck ; unless the conditions are exceedingly good, 
perfect in fact, nothing is found. To exemplify this, I will give 
an experience of my own when in the Dafla Hills. 
Shengorh Peak was one of my Trigonometrical Stations, and 
I had to clear the forest before 1 could commence observations, 
Rain set in soon after pitching camp; so I had plenty of leisure to 
collect in Natural History. The wet brought out the shells and 
slug-like forms, and I had a busy time making drawings and taking 
notes of colour and size. I secured what in drier weather I should 
never have got, certainly not alive; among them was this unique 
Genus Staffordia, whose nearest relative known to us is found at 
Chantaboon in Siam. It doubtless occurs at many intermediate 
places which have yet to be discovered, when its possible ancient 
connection with Assam may be explained. 
This is the history of a visit to one high point, one which over- 
looked the great broad valley of the Subansiri, extending far back 
to the base of the suowy range, away to hundreds of peaks covered 
with primeval forest. The imagination fails to picture what the 
result of exploration would be, combined with knowledge of how 
and what to collect. In these solitudes Nature reigns supreme ; 
one does not often find such a spot—seldom visited by man, 
never lived in by him. 
The birds on this Peak were fearless. I was quite struck by the 
behaviour of a beautiful little Suthora, which kept hovering about 
my head and would perch on a twig a yard from my face. 
Starting with Sikhim and the valley of the Teesta, where species 
are numerous, I take in succession going eastward the great valleys 
of the Eastern Himalaya to the Brahmaputra, they go far back 
in geological time—are older, in fact, than the Sivaliks, for down 
their courses all the waste of the Himalaya has passed either to the 
sea, as in the case of the Teesta, or to build up the above formation, 
The vast thickness of these Tertiary rocks, originally deposited not 
far ahove sea-level, the basement beds being even marine, as near 
Samaguting, is well seen on the Assam Range south of the Brahma- 
