BY THE REV. J. E. TENISON-WOODS. 
1007 
Helix it is no use to catalogue species without adopting sectional 
divisions, which has been done in the present list. It must 
be admitted that they are not easy to identify, as the features 
are so feeble, and there is so little to go upon. Still the sections 
may be of some assistance, and they are meant to have no higher 
value in classification. 
With the genera it is difierent, and except in such a case as 
Nanina the divisions are well marked, and can hardly be mistaken 
one for another. In the smaller genera the features are very 
pronounced, that is genera small in point of numbers, not of size. 
I believe it may further be said that all the species of the genera 
Trochomorpha, Bidimus, Cyclotus, Cyclophorus and Alycceus, 
though perhaps not well distinguished from one another, are 
referable to a type which has certain well-defined geographical 
limits. With a little experience a species of Cydophorus^ for 
instance from the Malayan Peninsula, could be easily recognized 
as belonging to the region ; but it would require a prolonged 
familiarity to distinguish between the characteristic types of the 
various islands, as for instance Java and Sumati'a. The Bornean 
shells are easily recognized, though there are strong resemblances to 
the types of the Philippine Islands. 
Amongst the shells enumerated there is no foreign element. No 
molluscan animals, as far as it is known, have been introduced 
from foreign regions, and Ijecome iraturalized in the region now 
described ; but the large introduction of Euiopean and Chinese 
plants will alter this state of things Ijefore long, if it has not done 
so already. 
The following list has been taken from various sources. No 
special study has ever Vjeen made of the laml mollusca of the 
Malayan Archipelago. But owing to the labours of Pfeift'er and 
Albers, the task of compiling this list has been very much 
facilitated. The whole references in the case of every s[)ecies 
liave not Iteen given. As far as |)o.ssibl(! tluj refemmes ai-e made 
to three or four of tin; most easily accfjssible works, where more 
than one author has given a d(!Sci’iption. The woi k of I’feifl'er 
Gl 
