PLANISPIRA. 163 



unicolorous forms, the shells of the Cuming collection in the 

 British Museum showing a broad supra-peripheral band 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 

 banclless. 



135. Planispira ? armstrongi, Smith. 



Helix (Plectotropis) armstrongi, Smith, Proc. Malac. Soc. London, 

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



Original description : " 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 6-6 j, lente et regulariter accrescentes 

 leviter convex iusculi, supra suturam perspicue marginati, costulis 

 confertis obliquis arcuatis et pulcherrimegranulatis ornati, ultimus 

 infra carinam subserratam convexiusculus, prope carinam im- 

 pressus, costulis vel plicis curvatim radiantibus granulatis instruc- 

 tus, antice paulo descendens, circa umbilicum perspectivum 

 rotundatus ; apertura angulariter lunata, obliqua, inferne recedens, 

 zona externa supra carina picta ; peristoina superne tenue, leviter 

 expansum, obliquum, vix arcuatum, margine inferiore valde 

 arcuato, paulo incrassato, subreflexo, supero callo crasso recto 

 juncto. 



"Diam. maj. 28, min 25, alt. 14 mm.; apertura 7 longa, 

 11 lata." (Smith.) 



Hob. Burma (Armstrong). 



" The 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." (Smith.) 



The present species stands somewhat isolated in the Indian 

 and Burmese fauna, rather recalling some species of Pleurodonte 

 (section Caracolus), such as P. bornii, Pfr., and P. fozonaZis, Desh., 

 from the West Indies. In form it approaches nearest to Plani- 

 spira (Trachia) trochalia, 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 costae 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 examination 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 shell and 

 with such coarse granulated costae. 



M2 



