PLATE CXX. 



FIG. I. 

 BULLA APERTA. 



OPEN BULLA OR BUBBLE. 

 GENERIC CHARACTER. 



Shell suboval, Aperture oblong, very patulous, and smooth or even. 

 One end convoluted. 



SPECIFIC CHARACTER 



AND 



SYNONYMS. 



Shell almoft entirely open, subrotund, pellucid, and faintly striated 



transversely. 



Bulla Aperta: testa subrotunda pelluclda transversim substrlata 

 tota hiante. Gmel. Linn. Sj/st. Nat. T. 1. 

 p. 6. sp. 3424. sp. 8. 



Bulla pelluclda, fragilissima, tota hians, s. apertura ampllssima. 

 Da Costa. Brit. Conch, p. 30. sp. 16. 



Da Costa says, all the shells of this species he knew, were fished up 

 near Weymouth in Dorsetshire, and not any where else on the 

 British coast ; they are even not frequent there ; so that it seems a 

 rare as well as curious shell. — ^To this we may add, that they are 



d2 



