1888.1 471 [Newell. 



tre of figure. The sides of the shell folded in, approach in some 

 specimens, to within 3 to 4 mm. In length the slit thus formed 

 equals that of the dorsal opening, which crosses it at right angles, 

 and also the length is about one-half the diameter of the living 

 chamber. The dorsal aperture has a slight saddle, the back of the 

 shell being bent forward in some of the specimens. Thus the ap- 



Aperture. 

 Lateral view. Ventral view. 



erture is widest at the three extremities, and narrow in the centre. 

 The openings vary in width from 3 mm. in the narrowest places to 

 8 mm. near the extremities, and are proportionally narrower in 

 the younger than in the older shells. 



The siphon is circular, 3 mm. in diameter in the larger speci- 

 mens, and is situated from 5 to 8 mm. from the ventral side. Faint 



