466 CHRYSOSTOMA. 



Genus CHRYSOSTOMA Swainson, 1840. 



Chrysostoma Swainson, Shells and Sliell-fish, p. 353. 



The operculum is corneous, thin, a little convex and shining 

 within, a little concave outside, with fine radiating strise ; there are 

 5 whorls, the nucleus central. It will be seen that this organ re- 

 sembles that of Euchelus rather than of Umbonmm or Trochus. 

 The radula has teeth considerably like Monodonta and Diloma. 

 (See Troschel Das Gebiss, ii.) 



C PARADOXUM Born. Vol. X, pi. 45, figs. 91, 92. 



Shell globular, imperforate or nearly so, thick and strong, with a 

 porcelaneous texture. Surface smooth, with scarcely visible lines of 

 growth, the upper whorls microscopically, densely, spirally striated. 

 Color whitish, closely reticulated and mottled all over with red or 

 pinkish, often with a few large darker maculations above. Spire 

 very short ; sutures linear, bordered by a slight concavity of the 

 whorl or margination. Whorls 6, convex, the last globular. Aper- 

 ture half-moon shaped, reddish or golden-orange color within ; 

 parietal wall covered with a very thick orange-colored (rarely 

 crimson) callus, which projects in a short tongue-shaped lobe above 

 the slight, often closed, umbilical perforation. 



Alt. 21, diam. 23 mill. ; alt. 18, diam. 17 mill. 



Singapore ; Celebes ; Mergui Archipelago ; Philippines ; New Cale- 

 donia. 



Helix paradoxa Born, Test. Mus. Cses. Vindobon., p. 394, t. 13, 

 f. 16, 17, 1780. — Chrysostovim Nicobaricm, etc., Chemnitz, Conchyl. 

 Cab., V, p. 216, t. 182, f. 1822-1825, 1781.— Tm-6o nicobaricus 

 Gmel., Syst. Nat. xiii, p. 3596. — Philippi, Conchyl. Cab., p. 34. — 

 Reeve, Conch. Icon., f. 48. — Chrysostoma nicobaricum Chem. 

 Chenu, Manuel, f. 2618. — Crosse, Journ. de Conchyl., xiv, p. 116, 

 t. 5, f. 8 {operculum). — Trochus nicobaricus Gni., Fischer, Genre 

 Turbo, in Coq. Viv., p. 68, t. 36, f. 5. 



