COSCnOLOGY. 1G3 



Sul)-nr<l(.r PNEUMOBRAXCEIA TA . 



Terrestrial air-breatliers. Shell closed by an operculum, whicli is occasionally 

 {Biplommatiiui) retracted out of siglit from the aperture. Tentacles contractile 

 simply, not retractile by inversion, as in the Ilelicida;. Sexes distinct. Tlie oper- 

 culum is very variable, being spiral and liorny as in Ci/clophorns ; spiral and shelly as 

 in Hi/bocystis ; or non-s])ii'al and shelly as in Hdicina, with numerous curious modi- 

 fications in different genera. The Burmese species embrace some of the smallest 

 land shells as vrell as the largest found in that region. 



Fiuaihj TruncatellidEe. 



TEUyCATELLA, RlSSO. 



Operculum homy, subspiral. Apex of shell decollated. 



,, VALIDA, Pfr. Arakan Coast. 



These small shells are littoral in their habits, and always found close to the sea. 

 They walk something like a leech, whence their name of ' looping snails.' 



Famihj Acmellidse. 



AciTELLA HTALINA, Thcob. and Stol. Miuilmain. 



,, MoRELKTi.vxA, Nov. Batto Malvc. Nicobars. 



,, EoEPSTOKFFiANA, Nev. Katchall. Nicobars. 



The natural position of those small shells was regarded by Stoliczka as inter- 

 mediate between the Rissoidie and Cyclopltoridce. The single species from Maulmain 

 is extremely rare. 



Familij Cyclophoriclse. 

 Operculum spiral, horny, shelly ; or composite, partly horny, partly shelly. 



rOMATIASIN^E. 

 PoMATiAS, Stiider. 



Operculum cartilaginous, paucispiral, and formed of two lamina', one outer and 

 one iuner. Shell turrited. 



,, PEGUENSis, Tlieob. Gwali Hill. Arakan Coast. 



CYCLOPnORIN^. 



CrcLOPHOErs, Monffort. 



Operculum horny, multispiral. Shell turbinate. 



,, PEENOBrLis, Gould. Tenasserim. 



A splendid shell of G4 mills, diameter. Mouth usually rich orange red, but 

 sometimes white. 



,, AHEAXTiAcrs, Schum. Amherst and Maulmain. 



This is an eipially fine shell, and seems the representative species of the last in 

 Martabun. 



,, TnE0B.u.DiANns, B. Tondoung near Thayet-myo. 



The figure in the Conchologia Indioa, pi. cxliv. fig. 2, is a var. of C. speciosus, 

 Pliil., and quite unlike Benson's species. 



„ PULGXTEATUs, Pfr. Pcgu. Mimboo. 



This is a veiy variable shell in .size and colour, ranging from 47 mills, to 31 mills. 

 The lip is somtimes deep orange, sometimes pale or yellowish, and rarely white. In 

 hot and arid spots a dwarf race is found of only 19 mills, diameter. 



,, jjATESs, W. Bl. Pegu and Arakan Hills. 



A small solid race closely allied to the last. 



