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Show 104 MB. E. A. SMITH ON LAND-SHELLS EBOM [Eel). 5, suture. Although not mentioned by Godwin-Austen, there are microscopic spiral or concentric stria? on the base, and, near tbe keel, they are quite evident, even under an ordinary lens. Nanina sarawakana, Dohrn, appears to be very near this species. 10. DYAKIA SUBDEBILIS. (Plate II. fig. 11.) Testa sinistrorsa, tenuis, anguste perforata, pallide fuscescens, ad carinam medianam et suturam linea pallida cincta; spira depresse conica, ad apicem obtusa; anfractus 6, lente accrescentes, planiusculi, supra suturam impressi, lineis incrementi oblique arcuatis sculpti, minute granidati, granulis minutissimis in seriebus spiralibus plus minus regularibus dispositis ; anfr. ultimus ad peripheriam acutissime carinatus (carina utrinque compresso), infra convexiusculus, nitidior quam supra, similariter insculptus; apertura angusta, obliqua ; peristoma tenuissimum, margine columellari ad insertionem paulum reflexo. Diam. maj. 23 millim., min. 20, alt. 11. Hab. Sarawak (C. Hose). The precise locality of the single specimen presented to the British Museum by M r . Hose is unknown, but it may possibly be Baram. With the exception of D. moluensis of Godwin-Austen, this species is smoother than any of the Bomean forms of Dyakia, 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. TEOCHONANINA. 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, JNatuna, 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 T. conicoides under the varietal name of parva. Having reexamined these specimens, together with the fresh material collected by M r . Everett, I a m now of opinion that it will be more philosophic and satisfactory to designate, by separate names these forms, which, although bearing such a strong general resemblance 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 difliculty in at once regarding them as distinct species, and it would be absurd not to do so, but when the various intermediate forms present themselves w e are puzzled how to proceed. |