38 



Cyclostoma strigatum. Testa solida, orbiculato-conica, pal- 

 lide beryllina, supra costulis cingulata, infra sub-planulata, um- 

 bilico amplo et carina acuta impendente limitato perforata : 

 spira anfr. 5 convexis, sutura bene discretis, ultimo prope aper- 

 turam despecto, fere disjuncto : apertura circularis ; peristomate 

 simplici, everso, acuto. Lat. 2 9 n , alt. T 3 ff poll. Hab. Upolu. 



Not half so large as the preceding, and may be known by its 

 uniform fluting, its sub-globose form, its plain, flattened base, 

 and ample tunnel-shaped umbilicus, margined by an overhang- 

 ing carina. 



Cyclostoma plicatum. Testa parva, solida, rudis, pyrami- 

 data, cinereo-virens, plicis confertis obliquis rugata, et striis 

 minutis volventibus cincta : spira acuta, anfr. 6 rotundatis et 

 sutura bene discretis, ultimo ad peripheriam rotundato ; infra 

 convexa et umbilico modico acute marginato perforata : apertu- 

 ra circularis ; peritremate simplici. Lat. f, alt. § poll. Hab. 

 Upolu. 



Differs from the preceding in its more elevated, acutely coni- 

 cal form, its plaited whorls without prominent revolving lines, 

 its rounded periphery and base, and its more contracted umbili- 

 cus. The young are discoidal, without folds, but with somewhat 

 nodular spiral lines and bright beryl-green color. 



Cyclostoma obligatum. Testa parva, crassa, sub-globosa, 

 cinerca, arete perforata, utrinque sulcis et costulis acutis sub- 

 crcnulatis equalibus cincta, et lineis incrementi subtilissimis 

 striata : spira acuta, anfr. 5 rotundatis : apertura parva, ovata ; 

 peristomate simplici, crasso. Lat. T 5 ^, alt. f poll. Hab. Matea. 



Still smaller than C. rugatum, and remarkable for its solid 

 structure, its coarse alternate ridges and grooves, and its small 

 ovate aperture. It looks not unlike some specimens of Littorina 

 rudis. 



Cyclostoma diatretum. Testa planorboidea, albido-cornea, 

 supra costis distantibus, ad intervallos cincinne clathratis, angu- 

 lata, lute umbilicata : spira planulata, anfr. 4 cylindraceis, rapi- 

 de crescentibus, prope suturam decliventibus : apertura circu- 

 laris; peristomate simplici. Lat. f, alt. £ poll. Hab. Sandal- 

 wood Bay, Feejee Islands. 



Answers very nearly to the description of C. orbella, Lk. The 



