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Family III. Bullacea. 



Creatures that dwell at ease in quiet waters. 

 Where no mid waves lift up their crests of foam, 

 Nor furious winds lay hare the lone sea-caves 

 Which Nereids haunt, as fabling poets tell. 



This family, with its one solitary genus. Bulla, comprises 

 a small group of mollusks, provided with a fragile, lightly- 

 convoluted shell, either partially or altogether concealed 

 within the mantle. 



Linnseus included within the genus Bulla many species 

 of very dissimilar construction, but Bruguiere introduced 

 a complete reformation, retaining it for the reception of 

 those thin, fragile, bubble shells of which the Bulla fasciata 

 or lignaria may be regarded as the type. 



We may consequently assume that the molluscous occu- 

 pant of the genus Bidla is an inhabitant of comparatively 

 still waters, where the waves gently heave, and then subside 

 upon a sandy shore ; or else that the creature dwells deep 

 beneath the main. We may see in this adaptation of the 

 simple mollusk to calm waters, a beautiful illustration 

 of the proverb that " God tempers the wind to the shorn 

 lamb.''^ The fragile shell of the solitary Bulla is utterly 



