274 HELIX-PLANISPIRA. 



shell, and especially by the stiff, short but not very thickly standing 

 hairs covering the outside of the shell, etc. 



The synonymous H. boxalli of Sowerby is figured on pi. 37, fig. 

 50. 



Section II. PLANISPIRA Beck, 1837. 



Planispira BECK, Index Molluscorum, etc., p. 29 (subgenus 25th) ; 

 first species H. exceptiuncula Fer. ALBERS, Die Heliceen (edit. v. 

 Martens, 1860), p. 160, type H. zonaria L. SEMPER, Reisen im 

 Arch. Phil., Landmoll., ii. PFR., Nomencl. Hel. Viv. p. 181, 1878. 

 v. MARTENS, Preuss. Exped. nach Ostas., Landschn., p. 295. TAP- 

 PARONE CANEFRI, Ann. Mus. Civ. Genov. xix, p. 162, 1883. 

 Pusiodon SWAINSON, in part. Philina ALBERS, Die Hel. 1850, in 

 part. 



This section differs from Chloritis proper in the white or pale 

 shell, banded with brown, and having a smooth apical whorl, and 

 the more oblique aperture. It may be divided into two divisions of 

 slight systematic value. 



1. Planispira s. s. No crest-like ridge behind the lip; aperture 

 decidedly wider than high ; basal lip usually more or less thickened 

 or toothed. 



2. Cristigibba. A crest or gibbous ridge behind the lip ; aper- 

 ture about as high as wide; basal lip narrow, not thickened or 

 toothed. 



1. Subsection Planispira (restricted). 



Shell depressed, with flattened spire, the apical whorl smooth, 

 depressed ; umbilicus narrow, rarely covered ; last whorl deflexed 

 in front, usually constricted behind the reflexed peristome, aperture 

 very oblique, wider than high ; ends of the peristome approaching 

 but not connected by a raised callus ; brown-banded on a white or 

 pale ground. 



A group of snails very characteristic of the Moluccas, ranging 

 from Celebes to western New Guinea, and replacing to a great 

 extent in this region the other forms of Chloritis. 



Key to the groups of species of Planispira. 



Surface showing under a lens hairs or hair-scars. 

 Imperforate or very narrowly perforate, 



Group of H. exceptiuncula. 



