342 MR. E. A. SMITH OK" KEW 



from various localities in the nortli or north-eastern part of the 

 island, several of which have not previously been explored for 

 specimens of natural history. 



I would direct special attention to the remarkable forms of 

 Opisthostoma and Diplommatina. Of the former only two species 

 from Borneo were known prior to the discovery of the remark- 

 able O. grandispinosum^ , O. pulchellum, and 0. Sosei, which 

 were described by Grodwin-Austen. I have now the pleasure of 

 adding five additional species to tbe list, one of which at least 

 (0. mirabile) is a worthy rival of 0. grandispinosum, the most 

 wonderful of the known ones, in the beauty of its structure. 



Of Diplommatina ten Bornean. species have already been de- 

 scribed ; six more are now added, of whicb D. excentrica and 

 D. Everetti are very grotesque forms. 



Of Arinia, a genus not hitherto known from Borneo, two 

 species are here recorded. 



Mr. Everett has promised further collections, and the new 

 and interesting species they may contain I hope to describe in a 

 future paper. 



1. Najsina (Xesta) moluensis. (PI. XXV, fig. 1.) 



Testa anguste perforata, orbicularisj superne breviter eonica, tenuis, 

 polita, subpellucida, virescenti-albida, zona angusta saturate brunnea 

 supra suturam et supra medium anfractus ultimi cincta, circa peripheriara 

 fascia lata dilutiore, alterse juncta, ornata, increment! lineis tenuissimis 

 striisque spiralibus exilissimis utrinque sculpta; anfractus 5|, regulariter 

 crescentes, infra suturam anguste et impresse marginati, ultimus baud 

 deseendens; apertura parum obbqua, late lunata; peristoma tenue, 

 margine columellari oblique, leviter incrassato, albido, supra umbilicum 

 breviter reflexo. 



Alt. 16 millim., diam.maj. 2b\, min.21. Apertura lOf longa, 12 lata. 



Sah. Molu or Mulu Mountains, N. Borneo. 



This species appears to be distinct from the allied forms of 

 Xesta and is distinguishable by its form and coloration. 



2. SiTALA EARICOSTULATA. (PI. XXV. fig. 2.) 



Testa turbinata, eonica, subrimata, pallide fuscescens ; anfractus 7, lente 

 crescentes, tres prinii liris tenuibus 5-6 spiralibus cincti, cseteri costulis 

 leviter obliquis subremotis baud sequidistantibus instructi, ultimus ad 



* Unnecessarily placed in a new genus (Geothauma) by Crosse, Journ. de 

 Conch. 1892, p. 282. 



