Mollusca. 55 



distribution of several of them. The other genera represented at 

 Christmas Island — Pythia, Melamjms, Truncatella, Assiminea, 

 and Leptopoma — are also recognized as containing species which are 

 very widely distributed. 



In conclusion, therefore, it may be stated that the fauna, as 

 represented by the terrestrial Mollusca, does not show any special 

 affinity with that of any other parti cidar locality ; and that the 

 same species, or others very similar, might be expected to occur 

 not only at adjacent localities, such as Sumatra or Java, but also 

 further eastward in jS'ew Guinea and some of the Pacific Islands. 



Family ZONITID^. 

 1. Lamprocystis normani (Smith). (PI. VIII, Figs. 1-3.) 



Ariophanta {Microcystis) iiormaui, Smith, P.Z.S., 1888, p. 537. 



Testa parva, plus minus depressa, anguste perforata, tenuissima, 

 nitida, vel pellucida et dilute fusco-cornca, vel magis opaca, fusca, 

 infra suturam et ad basim pallida, supra et infra microscopice 

 spiraliter striata ; spira brevissime couoidea ; anfractus 5-6, lente 

 accrescentes, convexiusculi, ad suturam anguste marginati, ultimus 

 ad peripheriam acute rotundatus aut vix angulatus ; apertura 

 obli(^ue lunata ; peristoma tenue, marginibus distantibus, colu- 

 mellari ad insertionem breviter expanse et reflexo. Diam. raaj. 6^, 

 min. 6 mm.; alt. 4^ mm. Exemplum majus : diam. maj. 7f, 

 min. 7 mm. ; alt. 5^ mm. 



This species is variable in size, form, and colour. The typical 

 specimens were uniformly pellucid, horny, and thin in texture, 

 whilst some of those obtained by Mr. Andrews are more solid, 

 larger, and of a brownish or reddish brown colour, but pale 

 beneath the suture and upon the base of the body-whorl. Some- 

 times the upper surface, with the exception of the apex, which 

 is palish, is of a uniform reddish brown tint. The spiral striae 

 are only visible under the microscope, and are less conspicuous on 

 the under surface than above. 



2. Lamprocystis mabelae (Smith). (PI. VIII, Fig. 4.) 



Ariophanta {Microcystis) niahelcB, Smith, P.Z.S., 1888, p. 537. 



Testa L. novmani simillima, sed magis depressa, anfractibus 

 mim;s convexis, distinctius striatis, ultimo ad peripheriam subacute 

 angulato. Diam. maj. 6, min. oj mm. ; alt. 3^ mm. 



Collected by Mr. J. J. Lister. 



This species, if the specimens upon which it was founded be adult, 

 is a little smaller than the preceding. It is similarly perforated, 

 of the same texture and glossy appearance, but more depressed, 

 and has flatter whorls which are a trifle more distinctly spirally 

 striated ; the body-whorl is quite angular, and consequently the 

 fonn of the aperture is rather diff'erent. 



