PLANI9PIRA. 163 



unicolorous forms, tlie shells of the Cuming collection in the 

 British Museum showing a hroad supra-peripheral hand which 

 ascends the spire and is visible above the suture on all the 

 whorls, while below the periphery several narrow bands occur. 

 The shells figured by Ferussac, Pfeiffer, and in Conch. Ind. are 

 bandless. 



135. Planispira ^ armstrongi, Smith. 



Hdi.f (Plectotropis) armatront/i, Smith, Proc. !Malac. Soc. London, 

 i, 1895, p. 219, text-figure.' 



Original deserljdion : — '• Testa depresse conica, in medio acute 

 carinata, late umbilicata, solidiuscula, albida, zona purpureo-rufa 

 latiuscula, spiram ascendente, supra ornata ; spira breviter conica, 

 ad apicem obtusa ; anfractus G-Q^r lente et regulariter accresceutes 

 leviter convexiusculi, supra suturam perspicue luarginati, costulis 

 confertis obliquis arcuatis et pulcherrimegrauulatis ornati, ultimus 

 infra carinaui subserratam convexiusculus, prope cariuam im- 

 pressus, costulis vel plicis curvatim radiantibus granulatis insti-ue- 

 tus, antice paulo descendeus, circa umbiHcum perspectivum 

 I'otundatus ; apertura angulariter lunata, obliqua, in feme recedens, 

 zona externa supra carina picta ; peristoma superne tenue, leviter 

 expansum, obhquum, vix arcuatum, margine inferiore valde 

 arcuato, paulo incrassato, subreflexo, supero callo crasso recto 

 juncto. 



" Diam. niaj. 28, inin 25, alt. 14 mm. ; apertura 7 longa, 

 11 lata." (.Smith.) 



Hub. Burma (Armsirong). 



" Tlie costulations on the upper surface become stronger as the 

 shell increases, and the granules are also stronger upon the body- 

 whorl than upon the rest of the spire. The acute periphery has 

 a finely scalloped appearance when the shell is viewed from above 

 or below." (Smilh.) 



The present species stands somewhat isolated in the Indian 

 and Burmese fuuna, rather recalHng some species of Pleurodonte 

 (section Caracolas), such as P. honiii, Pfr., and P. bizonal is, Desh., 

 from tbe West Indies. In form it approaclies nearest to Plani- 

 spira {Trachia) trocJialia, Benson, from the Andaman Islands, but 

 that species has a narrower umbilicus and the margins of the 

 peristome are not united by a raised ridge on the parietal wall, 

 and it also lacks the strongly granulated transverse costje of 

 P. armstrongi. 



It is not without hesitation it is placed in Planispira in the sub- 

 genus Trachia, but until specimens with the soft parts are taken, 

 and their examiuatiou shall prove the contrary, this appears to be 

 the only course to adopt. Mr. Smith referred the species to 

 Plectotropis, but in this view I am unable to concur, as I do not 

 know any species of that group possessing so solid a sliell and 

 with such coarse granulated costal. 



M 2 



