4G4 On the Layid- Shells of the Natuna Islands. 



columella crassa antice rostrata, in medio dente valido munita ; 

 labium duplex, aurantium, raargine interne incrassato, externo 

 expanse, inferne angulatira producto. 

 Longit. 2-5 millim., diam. 1-3 ; apertura cum labro 1. 



Ilab. Bunguran. 



Across the body- whorl above the aperture a translucent 

 line is visible, apparently indicating an internal lira. I have 

 named this species after Herr Strubell, of Frankfort, who has 

 kindly communicated to me a list of the species of land-shells 

 known to him from the Natuna Islands. 



30. Diplommatina congener. (PI. XVI. fig. 18.) 



Testa dcxtrorsa, ovata, supeme producta, imperforata, rufo-succinea ; 

 anfractus 7, supremi duo subglobosi, la)ves, caeteri convex! costulis 

 tenuibus obliquis instructi, in interstitiis spiraliter microscopice 

 striati, penultimus ultimo latior, ultimus supra aperturam ad 

 lineam nigrescentem peculiariter contractus ; apertura subrotun- 

 data, ad basim columellic levitcr oblique canaliculata ; columella 

 obliqua, in medio dente parvo munita, superne labro callo juncta ; 

 labrum intus incrassatum, aurantium, externe expansum, paulo 

 infra suturam angulatim productum. 



Longit. 3 millim., diam. 1 ; apertura "75 longa. 



Hah. Bunguran. 



The constriction above the aperture indicated by an almost 

 perpendicular blackish-red line is very peculiar and at once 

 distinguishes this species from its allies. 



It is smaller than D. symmetrica^ Smith, from Xorth 

 Borneo, and is furnished with a tooth on the columella, which 

 is wanting in that species. The name symmetrica being 

 already in use for a species of this genus from New Guinea, I 

 take this opportunity of substituting that of gomantonensis 

 for the Bornean shell. 



31. Ilelicina Alarfensi, Issel. 



Helicina Martensi, Smith, Ann. & Mag. Nat. Hist. 1894, vol. xiii. 

 p. 69. 



Hah. Sirhassen. 



Var. parva. 



Smaller than the tyjiical form and a trifle more globose. 



Hah. Bunguran. 



Tlic form of this species which occurs at Bunguran is 

 considerably smallor than that from Sirhassen and is rather 

 more globose. 



