OF MOLLUSCA. 



189 



-whorls close- pressed, more or less covered with a polished coat ; 

 aperture lunate, with a fold forming a slight truncate canal at the 

 columnar angle. Peristome simple, acute ; throat and inner lip 

 with spiral laminse ; axis covered with a callous deposit ; the septa 

 between the upper whorls absorbed. 



1. Proserpina (see p. 86). 



Shell polished all over. (Mantle expanded and reflexed over the 

 upper and under part of the shell ?) 



1 . P. nitida. 



2. Ceres. 



Shell rugose and covered with a periostraca above, smooth and 

 polished and covered with a thin callous coat beneath. Mantle free 

 from the back of the neck, with a thick double-edged collar, the 

 outer edge rather reflexed. The front part of the upper surface of 

 the foot near the axis of the shell is depressed into a rather expanded 

 concavity which is lined with an extension of the mantle, having a 

 raised edge near the margin of the concavity. This raised edge is evi- 

 dently a continuation of the edge of the mantle of the body, sinuated 

 at the columnar and outer upper angle of the mouth of the shell. 

 It is more developed and crumpled up, in the specimens in spirits, on 

 the left side of the concavity ; and there is little doubt, in the living 

 state, that this extension of the mantle is expanded out and deposits 

 the polished callous coat of the under surface of the shell and the 

 callosity over the axis ; hence the larger size of the left side of the 

 extension. 



1. C. Salleana. Spire convex ; whorls granulated above. 



2. C. eolina. Spire flat ; whorls with oblique diverging raised lines. 



Lingual membrane of Ceres Salleana broad, elongate, with nume- 

 rous longitudinal series of teeth. Teeth 00-5-1 -5 -00 (fig. 100); 



Fig. 100.— Teeth of Ceres Salleana. 



the central tooth oblong, distinct, with a broad simple reflexed tip ; 

 the first and second lateral teeth rather broader than the central one, 

 with a three-toothed recurved tip ; the third narrow, elongate, with 

 a slightly recurved end ; the fourth and fifth much larger, oblong 

 and irregular-shaped ; the fourth about half as wide as the fifth, with 

 three or four dentations on the inner side of the upper edge ; the 



