450 FISSURELLIDiE. 



shell is much nearer the front margin than in the other 

 genera of the family. 



Species of Macrochisma. 



angustata, A. Adams. hiatula, Swains. 



compressa, A. Adams. raaxima, A. Adams. 



cuspidata, A. Adams. megatrema, A. Adams. 



dilatata, A. Adams, producta, A. Adams. 



Genus PUPILLIA, Gray. 



Mantle coriaceous, entirely covering the shell, orifice 

 of anal siphon small, oblong, at the anterior third ; foot 

 granulated, shorter than the mantle. 



Shell internal, depressly-conical, surface nearly smooth ; 

 perforation large, oblong, sub-central ; aperture wide, 

 ovate, the margin entire, double, sharp, white-limbed. 



Syn. Pupilleea, Krau.ss. Pupillaca, Phil. 



Eai. P. apertura. Born, pi. 51, fig. 6. Shell, P. aper- 

 tura, fig. 6, a, 6, h. 



The striking peculiarity of this genus is the fact of 

 the shell being entirely covered and concealed by the 

 mantle. The shell may readily be known by the sharp- 

 edged, white border, which is received into the integu- 

 ment of the animal, like one of the valves of a Chiton. 

 Pupillia apertura is an inhabitant of South Africa. 



Genus CEMORIA, Leach. 



Mantle-margin simple, anal siphon prominent, tubular, 

 with six papillae in front, and four behind j foot with a 

 rudimentary, operculigerous lobe. 



