107 



rotundato-ovata, subeffusa ; peristomate simplici, nigrescente, um- 

 bilicum parvum subtegente. Dimens. lXf poll.; Ij-XtV P°H- 

 etc. 



Ditches in paddy-fields, Ousima and Loo Choo. W. S. 



Bithynia divalis. T. minuta, imperforata, ovato-conica, 

 solidula, kevis, olivacea ; anfr. 3-\- ventricosis, ultimo permagno. 

 Apertura parva, ovata, verticalis ; peritremate continuo ad colu- 

 mellam flexuoso. Axis -^ ; diam. ^ poll. 



Inhabits China, vicinity of Canton. Mr. Bowring. 



The genus is somewhat equivocal. It has an operculum more 

 like that of a true Paludina than of any other genus. 



Assiminea debilis. T. globoso-conica, solidula, luteo-cornea, 

 arete umbilicata ; anfr. 5 tabulatis, ultimo ad peripheriam sub- 

 angulato. Apertura rotundato-ovata, peritremate continuo, vix 

 incrassato. Alt. -£■$ ; diam. -fa poll. 



Loo Choo Is. W. S. 



Paler and less solid than any other described species ; more 

 elongated than the following, and differing in color. 



Assiminea rubida. T. ovato-conica, solida, impolita, stra- 

 minea aurantiaco tincta, perforata ; anfr. 6 rotundatis, sutura 

 profunda. Apertura parvula, pyriformis, peritremate continuo. 

 Alt. ■£■$ ; diam. -^ poll. 



Inhabits Loo Choo, on beaches. W. S. 



Rather smaller than the preceding, and distinguished by its 

 color and solidity. 



Melania libertina. T. elongata, turrita, truncata, luteo- 

 cornea, hie illic fuscata, lineis volventibus antice insculpta ; anfr. 

 5-j- convexiusculis. Apertura elongata tortuosa, labro albo pos- 

 tice sinuato, antice in canalem obtusam pi-oducto ; fauce livida. 

 Long, l^ ; lat. |- poll. 



Simoda and Ousima, in sluggish streams and ditches. W. S. 



Generally resembles M. Virginica and indefinite/,, Lea, which 

 has a more lax and elongated spire. The grooving varies, and 

 in some specimens is nearly wanting. 



Melania gracilina. T. subulata, truncata, imperforata, 

 tenuis, lasvis, olivacea, sulcis acutis remotis cincta; anfr. 7-}- 



