210 POPULAR BRITISH CONCHOLOGY. 



a very strong ligament^ leaving only an opening to receive 

 the food. As soon as the young shells are swallowed, 

 they come under the power of the two millstones, which 

 crush, and grind, and reduce them and their living contents 

 to a paste, in which state they enter the stomach. This 

 stomach is capacious, in the form of a sack of meal bound 

 at the mouth ; and in this deep sack the paste remains till 

 it yields its substance for the nourishment of the voracious 

 Bulla. Various are the methods by which the Lord enables 

 his creatures to supply their wants. He has given sharp 

 teeth to fishes and quadrupeds, and hard bills to birds ; but 

 though the Bulla has neither tusks nor beak, he has fur- 

 nished it with a gizzard, which still better answers its pur- 

 pose/' 



II. Akera hullata has a very thin, horny, transparent 

 shell, which is not, strictly speaking, convolute, for although 

 the last whorl covers the body of the others, it leaves their 

 edges exposed at the top ; the upper edge of the aperture 

 is separated from the last whorl so far back that the lip is 

 quite free and elastic, so that it can be bent inwards to 

 touch the opposite lip ; the lobes of the foot are so wide 

 that, when at rest, they coil over and invest a part of the 

 shell. This eyeless animal is tinged and mottled with pur- 



