PLATE CXX. 



rare only because they are local : in one part of the sandy bay of 

 Caermarthen, below Tenby, we found them in abundance. 



It is called " the Bubble" by this writer; who observes that it 

 exactly resembles a bubble or bladder of water. The aperture is so 

 extremely large that the whole shell lies open to view. The contour 

 is somewhat oval, and slightly involuted ; and the shell is not 

 umbilicated. 



This is certainly not Bulla patula of Pennant (Brit. Zool. No. 85. A.) 

 as Da Costa and Gmelin imagine. The figures in that work are 

 sometimes calculated to mislead the most attentive ; but as we are in 

 possession of the shell Pennant describes, we can venture to say 

 the two former writers are mistaken. The species Aperta was 

 unknown to Pennant, and the shell he figured from the Portland 

 Cabinet, under the specific name of Patula, is extremely rare. 



fig. ii. 



BULLA CYLINDRICA. 



NARROW BULLA. 

 SPECIFIC CHARACTER. 



Shell cylindric, smooth, white, and thin. 



Bulla Cvlindrica: testa cylindrica lasvi alba tenuissima. Gmel* 

 T. I, p. 6. p. 3433, sp>. 38. 



