AMPHIBOLA. 269 



panded and united together. The Amphibolida offer an 

 exception to the general rule, that Pulmonifers with a olosed 

 mantle- cavity are destitute of opercula. 



Genus AMPHIBOLA, Schumacher. 



Shell suh-globose, solid, rugose, umbilicated; spire de- 

 pressed, whorls angulated; aperture oval; inner lip with a 

 callosity in the middle; columella flattened and reflected; 

 outer lip with a sinus at the hind part. 



Syn. Ampullacera, Quoy. Thallicera, Swains. 



Ex. A. nux-avellana, Chemnitz, pi. 84, fig. 9. A. 

 (Ampullarina) fragilis, Quoy and Gaimard, fig. 9, a. Oper- 

 culum, A. nux-avellana, fig. 9, b, 9, c. Shell, A. nux- 

 avellana, fig. 9, d. 



The animals of this genus are found in great abund- 

 ance in New Zealand, living in pools of brackish water, and, 

 in certain seasons, burying themselves in the sandy mud. 

 The New Zealanders collect them and employ them as arti- 

 cles of food. 



Species of Antphibola. 



nux-avellana, Chem. obovata, Dkr. 



Sub-gen. ampullarina, Sowerby. 



Shell thin, whorls rounded; inner lip simple; outer lip 

 sinuated in the middle. 



Busbyi, Gray. pomum (Natica), Phil. 



fragilis, Quoy and Gaim. 



VOL. II. N N 



