1887] MOLLUSKS OF THE VITI ISLANDS. 177 



lunate ; peristome simple, straight above, acute, at the base thickened 

 with callus. 



Major cliam. 15, height 6-7 millim. 



As compared with T. ludersi it is smaller, differs in the ground- 

 colour, the umbilicus is not so large, and the bands are wider and 

 only two in number. 



11. Trochomorpha subtrochiformis. 



Heliv trochiformis, Gould (not of Ferussac), Expl. Exp., Shells, 

 p. 61. 



Helix eurydke, Mousson (not of Gould), Journ. de Conch. 186.5, 

 p. 170. 



Trochomorpha subtrochiformis, Mousson, Journ. de Conch. 1869, 

 p. 335, pi. 4. fig. 6 ; 1870, var. alho-striata, p. 122; Pease, Proc. 

 Zool. Soc. 1871, p. 474. 



Helix subtrochiformis, Schmeltz, Cat. Mus. Godeff. p. 95 ; 

 Pfeiffer, Mou. Hel. vii. p. 289. 



Mousson's var. albo-striata inhabits Kanathia, one of the Wind- 

 ward Islands, and the type is a Samoan species. The variety, which 

 is unknown to me, is described as follows : — 



" Spira fusco-nigrescens, strigis fransversis, albis, imperfectis, 

 eleganter ornata, ad basin fulvescens, cum zona peripherica fusca." 

 (Mousson.) 



It is probably distinct from the Samoan type. 



12. Trochomorpha themis, sp. nov. 



Trochomorpha (Discus) ludersi, Mousson (not of Pfeiffer), Journ. 

 de Conch. 1870, p. 122 (part.). 



I obtained numerous specimens of this species at Vanua Balavo, 

 where they were found adhering to the trunks of trees. It is also 

 recorded from Oneata Island. 



Shell with a narrow umbilicus, solid, sublenticular, not shining ; 

 strise very fine, obhque and crowded ; whitish horn-colour, with a 

 single dorsal and basal submarginal chestnut-brown line ; spire de- 

 pressedly conoid, obtuse ; suture with a depressed white margin ; 

 whorls 5|, depressedly convex, slowly and regularly increasing, last 

 one not deflected in front, acutely and compressedly carinated, keel 

 white ; base convex ; umbilicus about one eighth the major diameter 

 of the shell ; aperture and peristome the same as in T. corallina. 



Major diam. 14, height 6 millim. 



As compared with T. ludersi it is smaller, paler, has oidy half so 

 many hnear bands, strise finer and the umbilicus much smaller. 

 T. corallina is of a fulvous colour (very rarely whitish), the bands 

 are wider and paler and the suture has not got the white margin ; it 

 is also a little larger and smoother, and lives in a different station. 



13. Trochomorpha kantavuensis, sp. nov. 



Shell widely umbilicated, thin, fragile, pellucid, depressed, lenti- 

 cular, smooth, shining ; incremental strise fine, crowded, oblique ; 

 Proc. Zool. Soc— 1887, No. XII. 12 



