104 ME. E. A. SMITH OK LAXD-SUELLS FROM [Peb. 5, 



suture. Although not mentioned by God win- Austen, there are 

 microscopic spiral or concentric striae on the base, and, near the 

 keel, they are quite evident, even under an ordinary lens. Nanina 

 mrawal-ana, Dohrn, appears to be very near this species. 



10. Dyakia subdebilis. (Plate II. fig. 11.) 



Testa sinistvorsa, tenuis, anguste perforata, ■pallide fuscescens, ad 

 carinam medianam et sutiiram linea paUida cincta ; spira 

 depresse conica, ad ajncem ohtusa ; anfractns 6, lente accres- 

 centes, planiiisctdi, supra suturarn imjiressi, lineis incrementi 

 ohlique arcuatis sctdpti, mimde r/ranulati, grannlis minutissimis 

 in seriebus spiralihus plus minus regidarihus dispositis ; anfr. 

 ultimus ad peripheriam acutissime carinatiis {carina utrinque 

 compressa), infra convexiusculus, nitidior quam supra, 

 ftimilariter inscvlptus ; apertura angusta, obliqua ; peristoma 

 tennissimum, margine columellari ad insertionem paidum, 

 reflexo. 

 Diam. maj. 23 millim., min. 20, alt. 11. 

 Hah. iSarawak (C Hose). 



The precise locality of the single specimen presented to the 

 British Museum by Mr. Hose is unknown, but it may possibly be 

 Baram. With the exception of T). moluensis of Grodwin-Austen, 

 this species is smoother than any of the Bornean forms of DgaJcia, 

 and on this account is not likely to be mistaken for the young of 

 some of the larger species. It is coloured like the "first variety " 

 of the preceding species, but is a trifle paler ; it is, however, 

 differently sculptured and the whorls enlarge less rapidly. 



Trochos"anina. 



The present collection contains three forms of this genus which 

 cannot satisfactorily be referred to any of the known species 

 from Palawan, Balabac, Borneo, Labuan, ISatuna, Sulu, and 

 Philippine Islands. They agree with T. paraguensis. Smith, and 

 T. bongaoensis, Smith, in the thickened sinuous lower margin or lip 

 of the aperture, and the differences consist in size, colour, and 

 sculpture. Another species, the smallest of the whole series 

 having the thickened basal lip, was referred by the writer to 

 1\ eonicoides under the varietal name of parva. Having re- 

 examined these specimens, together with the fresh material 

 collected by Mr. Everett, I am now of opinion that it will be more 

 philosophic and satisfactory to designate, by separate names, 

 these forms, which, although beariug such a strong general i-esem- 

 blance to one another, are still recognizable by certain, although 

 perhaps only slight, differences. This is one of those cases which 

 occasionally present themselves, in which it is so difficult to come 

 to a decision. Take the two extreme forms of the series and there 

 is no difficulty in at once regarding them as distinct species, and 

 it would be absui-d not to do so, but when the various intermediate 

 forms prespnt themselves we are puzzled how to proceed. 



