100 UNIVALVES BULLA. 



vision the shells are less beaked, and more gibbous j 

 the C. naucum and C. ampulla may be mentioned as 

 illustrative examples : they are without teeth or spire, 

 and the greater part umbilicated. The species of the 

 fourth division are pyriform; of which the B. ficus and 

 B. rapa strongly resemble some of the Murices. The 

 fifth division being composed entirely of land shells, 

 and the animal inhabiting them being' oviparous, they 

 might with greater propriety be classed with the genus 

 Helix. The B. terebellum, the only species of the sixth 

 division, is a remarkable exception to the general form 

 of the Bulla; it is a long and slender shell, and not un- 

 like a lengthened olive. 



Some species of this genus, particularly those of the 

 fifth division, are banded with party-colored streaks, 

 but by far the greater number are colorless. 



The B. volva or true Weaver's Shuttle, is one of the 

 most rare shells of the genus. The B. imperialis, which 

 has a pink interior, is also considered rare. The re- 

 verse varieties of the fifth division are also highly valued. 



The different species of Bulla are found in almost 

 every part of the world. 



This g^enus derives its name from the resemblance 

 which some of the lesser species have to a bubble of 

 water (Bulla). 



Division h—Shell resembling the Cyprcea genus, but toothed on 

 the outer lip only. 



Scientific Name, Locality. Common Name. 



Ovum Amboyna, India, China • Egg Dipper • • - 



Imperialis South Seas Crumpled • do • • 



Nucleus ••• Mediterranean, Africa •■ Wrinkled • do •- 



Verr\jcosa • Amboyna, China Warty •• -do -" 



