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The specimens from Nusa laut are small, though probably adult, measuring only from 

 13 to 18 Mill, in their largest diameter. The largest specimen from Pulu Kelang, is 24 Mill, 

 in this dimension. 



18. Neritina (Clithon) flavovirens Busch. 



V. D. Busch. Phil. Abb. u. Beschr. neuer Conch. I, Neritina, PI. i, fig. 6. 



V. Martens. Martini-Chemn. Conch. Cab. Ed. II, Neritina, p. 184, PI. 19, fig. i, 2, 12. 



Weber, Zool. Ergebn. Band IV, Siiss- u. Brackw. Moll. p. 81, PI. 10, fig. 12, 15, 16. 



Stat. 33. River near bay of Pidjot, Lombok. i Spec. 

 Stat. 179. Kawa-bay, West coast of Ceram, river, i Spec. 



The only specimen from Lombok has a few spines, which are not mentioned by 

 V. D. Busch, but v. Martens has known this form, without mentioning the locality, and mentions 

 such specimens from Celebes, collected by Weber, mixed with a spineless specimen. I possess 

 10 specimens from several localities on Java, namely 4 from Besuki, one of which spined; 4 

 from Palabuan, all spined, and 2 spineless from the Pamenug-river. Lombok is a new locality 

 for the species. 



19. Neritina (Clithon) tialanensis Lesson. 



Lesson. Duperey, Voy. Coquille. Zoologie II, p. 379. 



V. Martens. Martini-Chemn. Conch. Cab. Ed. II, Neritina, p. 193, PL 20, fig. i — 24. 



Weber, Zool. Ergebn. Band IV, Siiss- u. Brackw. Moll. p. 82. 



Stat. 71. Near Makassar. 5 Spec. 



Stat. 125. Sawan, Siau-island. Reef. I Spec. 



The specimens from Stat. 71 belong to the vars. conferta v. Martens zxiA polydelta v. Martens, 

 with an intermediate specimen, that from Stat. 125, belonging to var. polydelta contains a small 

 crustacean, belonging to the Paguridae, which accounts for its being captured on the reef. 



Fam. Neritilidae Schepman. PI. VIII, fig. 5. 



The examination of the radula of the typical species of the subgenus Neritilia v. Martens, 

 has convinced me, that it not only belongs to a separate genus, but even to a new family, 

 which I have placed provisionally at the end of Neritina, though I think it is not its proper 

 place. The species has no rhachidian tooth, as far as I can see; though I have examined the 

 uncoloured and coloured radula I could not detect it; the first lateral (5,1) are very thin and 

 transparent, and only by colouring I could make out the complicated shape; it has some affinity 

 with the corresponding tooth in the Neritidae, but its position is much more in a perpendicular 

 direction, the margin seems to be reflected; at its proximal side, there is a projection or knob, 

 also with a reflected margin, apparently ending in a hook; by the smallness and thinness, it is 

 not easy to be satisfied on every particular, moreover a slight alteration in position, essentially 



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