1008 MALAYSIAN LAND AND FRESHWATER MOLLUSCA, 
( “ Monographia Heliceoruai Yiventium,” 8 vols.), is taken as the 
standard, but corrected according to his most recent determina- 
tions of species before his decease as contained in “ Xomenclator 
Heliceorum Viventium.” These works with his “ Moaographia 
Pneumonopomorum Viventium,” may be said to contain nearly all 
that has been done in this department of natural science. All that 
one requires in addition are the essays of Nevill, Benson, De 
Morgan, von Mbllendorff and Hungerford, and these are princi- 
pally contained in the Journal of the Royal Asiatic Society, 
Calcutta branch. 
To facilitate reference, a catalogue of works, mentioning species 
quoted in the list, is given. It is not by any means intended as 
an exhaustive bibliography of the subject, but it is hoped that no 
author is omitted who has described any Malayan land shell. It 
may be necessary to add that I have not been able to verify the 
references of every species, which of course would impose a vast 
amount of labour, and enormously increase the time required for 
the preparation of the catalogue. But in a great many instances, 
perhaps the majority, I have consulted the original authors espe- 
cially in the case of the older conchologists. 
It should be mentioned that Pfeiffer’s nomenclature of the 
families has been adopted, following also his orthography. 
LAND MOLLUSCA. 
Family STREPTAXID^. 
1. Streptaxis, Gray, 1837, Loudon’s Magazine, n.s. I. p. 484. 
oval or oblong, in the young state sub-hemispherical, 
deeply umbilicate, irregular and oblique from the lower whorls 
which rapidly increase in size, receding from the axis of the upper. 
Near the close of the penultimate whorl the umbilicus is compressed 
by a return to the original axis. 
