BULLA 



Bulla and Bullsea, Lam. 



TESTA plerumque tenuis, laevigata, ovata, vel 

 oblonga, plus minusve convoluta, spira brevi, 

 vel depressa, vel con(^ava ; apertura maxima, 

 fere longitudinem testsa sequante, plerumque 

 longitudinali, nonnunquam fere transversa, 

 rar5 lineari, antice latiore : epidermide tenui. 



In uniting the Bullaea? of Lamarck with his Bullae, we 

 think we are justified by the consideration that there is so 

 complete a transition in form from the oval and ventricose 

 Bullae, such as B. Ampulla^ to the only slightly convoluted, 

 and almost unrolled Bullaeae, that it is impossible to draw 

 the line of separation between the two. Perhaps we may 

 be blamed by Malacologists for thus uniting shells whose 

 animals apparently differ very materially, we think, 

 however, that whoever will carefully examine the animals 

 of both, will be convinced of the propriety of this union, 

 for a general resemblance and affinity will be observed 

 and it will be found that the principal points of difference 

 will be analogous to those very specific circumstances in 

 which the shells differ. 



The Genus Bulla as it has been established by Cuvier, 

 Lamarck and others consists of only a very small part of 

 the Linnean Bullae. We have already shown how widely 

 separated from genuine Bullae are the Lamarckian Acha- 

 tinae, Pyrulas, Ovulae and others which Linne and his 

 followers combined with them, wherefore we need not here 

 repeat the description of their distinguishing characters, 

 but may immediately enter upon the characters of Bulla 

 as we have here considered it, as consisting of Lamarck's 

 Bulla and Bullaea combined. 



