SCAPHANDER. 209 



skill, would in vain attempt to imitate. Let us touch a 

 little on one of them — Bulla ligtiaria, found at Whiting 

 Bay, by digging in the sand at ebb-tide. It is not easy 

 to give a description of this elegant univalve. It is oval, 

 convex, and slightly spiral, like a thin plate, pretty closely 

 rolled up at one end, and only half rolled up at the other. 

 Inside it is china-looking, and outside it is like wainscot. 

 It is nearly two inches in length, and at the broadest about 

 an inch and a quarter across. Never did lady recline on 

 a more tasteful couch. The internal structure of this well- 

 lodged mollusc is deserving of our regard. As the inhabi- 

 tant of the Bulla is as soft as a slug, one would think that 

 it would feed on something as soft as jelly : instead of that, 

 it swallows entire the fry of another creature with a shell as 

 hard as its own. This shell-fish is Mactra sichtruncata, 

 called in the Lowlands AiJcens, and in the Highlands Murech 

 haan ; haan denoting the colour, which is white, and murech, 

 it is probable, being the Celtic origin of the Latin Murex, 

 the shell-fish which yielded the Tyrian dye, or imperial pur- 

 ple. But how can this soft Bulla feed on this hard food ? 

 Though it has no teeth, it has an equivalent — a gizzard formed 

 of shell as hard as bone, and composed of two valves, or 

 rather millstones. These millstones are bound together with 



