1884.] OF THE 'challenger' EXPEDITION. 267 



cations of spiral striae en the under surface. Spire shortly conical, 

 obtuse at the apex, with almost straight lateral outlines. Aperture 

 moderately large, yellow within, subsemicircular. Peristome semi- 

 pellucid, slightly expanded and thickened, generally margined exter- 

 nally with a whitish stripe. Columellar side of the aperture oblique, 

 coated over the umbilical region with a glossy yellow callosity, 

 slightly cliannelled at the base. 



Greatest diameter 6 millim., smallest 5, height 5. 



Operculum thin, slightly concave externally, minutely rugose, 

 yellowish on the straight or columellar side, brownish or reddish 

 brown towards the outer edge, which is very finely carinate. 



Hah. Wild Island and Pigeon Island. 



This species is very like H. modesta, Pfr., from the island of 

 Tanra, but has a slightly larger mouth, a yellow basal callus instead 

 of a whitish one, and a different operculum, that of H. modesta 

 being thicker, more shelly, concave in the centre, with a broad 

 flattened raised rim all round the convex side and a raised but not 

 flattened margin on the straight side. 



"»' 



10. Pythia scarab^us, Linn. 



Hah. Wild Island. 



A large number of specimens were brought home from this loca- 

 lity. They arc, as a rule, rather larger than those obtained by the 

 Expedition at the Ke Islands, having an average length of about 

 29 millim. and a width of 17. They vary in colour, some being 

 painted like typical variegated forms, and others more uaifonnly 

 tinted like P. pollesc. Hinds, and P. albivaricosa, Pfeiffer, which 

 might be regarded as local varieties apparently offering no struc- 

 tural differences. 



11. Melania ARTHURii, var. ? 



Hab. Wild Island, Admiralty Islands. 



As far as I can ascertain, no species of Melania has been recorded 

 from these islands. The single shell at hand, which had been 

 seized upon by a Pagurus, approaches so closely to M. arthurii 

 (Brot) that I think it will probably prove only a variety of that 

 species. It is decollated above, four and a half whorls only re- 

 maining, of which the two uppermost, however, show the longitu- 

 dinal costse occurring in that species. The rest of the surface is 

 sj)irally densely striated and sculptured with rather elevated lines of 

 growth. It is of a dark brown tint, slightly paler at the margina- 

 tion below the suture, beneath which there is a series of oblique 

 dark oblong spots. The whorls are slightly convex, and somewhat 

 contracted just below the upper marginate edge. 



12. Neritina cornea. 



Hab. Wild Island. 



The two specimens correspond to the form figured by Martens in 

 his Monograph (Conchyl.-Cab. pi. 12. f. 15). 



