256 ADBOKBIS. 



alba, nitida, complanata, suborbicularis, umbilicata ; supra minu- 

 tissime et concentrice striata, subtus taviuseula; anfractibus 2>\, 

 rapide accrescentibus, ultimo compressiusculo, non carinato; 

 apertura subovata, parum transversa ; margioe dextro tenui, fragili. 

 Obs. A pellucid, shining, rather solid species, very finely concen- 

 trically striated. 



7. Angasi (pi. 256, f. 37, 38), A. Ad.— Testa valde depresso- 

 conica, late umbilicata, alba, tenuis, semipellucida ; aufractibus 

 rapide crescentibus, ultimo magno couvexo concentrice striate, ra- 

 diatim obsolete plicato, ad suturas crenulato, ad peripheriam 

 acute angulato et concinne crenato, ad basin radiatim corrugato- 

 plicato ; apertura semiovata ; labio rectiusculo, acuto ; labro 

 postice ascendente. Obs. This is the largest and most beautiful 

 species of Adeorbis yet discovered. It was found by Mr. G. F. 

 Angas in Coodgee Bay, outside Port Jackson Heads, on the 

 sand. 



S. Sinensis (pi. 256, f. 21, 22), A. Ad.— Testa discoidalis; 

 spira prominula, alba, subporcellana, opaca, striis incrementi ra- 

 diantibus et lineis spiralibus transversis decussata ; aufractibus 

 regulariter crescentibus, ultimo ad peripheriam obtuse angulato ; 

 umbilico patulo, perspective, margine carinato ; apertura qua- 

 drato-orbiculari ; labro mediocri. Obs. This is a rather large 

 opaque-white species, having very much the aspect of Ethalia, 

 but there is no trace of an umbilical callus. 



9. Japonica (pi. 256, f. 20), A. Ad. — Testa discoidalis ; 

 spira depressa; alba, nitida, tenuis, semidiaphana, radiatim striata; 

 anfractibus regulariter crescentibus, convexiusculis ; umbilico 

 patulo, margine valde carinato ; labro mediocri. Obs. The most 

 common species met with in the seas of Japan, not however cha- 

 racterized by any remarkable peculiarities either of form or sculp- 

 ture. 



10. clatjsa (pi. 256, f. 25, 26), A. Ad.— Testa discoidalis; 

 spint depressa ; albida, subdiaphana, striis incrementi radiatim 

 ornata; anfractibus rapide crescentibus, ultimo ad suturas vix 

 angulato, ad peripheriam rotundato ; umbilico callo, tenui, vix 

 clauso ; labro proclucto. Obs. In this species the umbilicus is 

 partly occupied by a callosity, as in some species of Ethalia. 



11. okbella (pi. 256, f. 16, 17), A. Ad. — Testa discoidalis; 

 spira planata; alba, subporcellana, nitida, semiopaca, radiatim 

 striata, basi transverse confertim sulcata ; anfractibus regulariter 

 crescentibus, ultimo ad peripheriam rotundato ; umbilico patulo, 

 perspectivo, margine rotundato ; labro subproducto. Obs. In 



