1008 MALAYSIAN LAND AND FRESHWATER MOLLUSCA, 



(" Monographia Heliceorum 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 " Nomenclator 

 Heliceorum Viventium." These works with his " Monographia 

 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 Mollendorff 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 

 i-eferences 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. 



Shell 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. 



