156 POPULAR CONCHOLOGY. 



tentacula. — There are only 2 species recent, 

 and 2 fossil. 



The Bullcea aperta is found in 

 the European Seas ; it climbs 

 aquatic plants well, but swims 

 badly. The Bullcea hirundinina 

 is found at the Isle of France. 

 The animal is of a beautiful blue 

 colour. 



30. Bulla. — Shell rolled up, aperture ex- 

 tending the whole length. Ani- 

 mal, head very indistinct; no 

 apparent tentacula ; hinder part 

 of the body covered by the shell, 

 which is external, and adheres by 

 a muscle ; foot large. - — 26 species 

 recent*, and 11 fossil. 



The Bulla can nearly, but not entirely, 

 enter into its shell : it swims well, and is found 

 in the seas of Europe, India, &c. The animal of 

 thei?. lignaria possesses a very singularly formed 

 testaceous substance within its body, not no- 



* Some of the recent species are also found in a fossil 

 state. 



