Bulla. MOLLUSCA. BRANCHIFERA. 295 



EXTINCT SPECIES. 



1. B. convoluta Cylindrical, smooth ; aperture linear, expanded a little 



way from the base; vertex obtuse, perforated. — Sower. Min. Conch, t. 

 cccclxiv. f. 1. — In Crag. 



2. B. constricia — Subcylindrical, contracted in the middle ; vertex trun- 

 cated, perforated ; base obscurely striated ; aperture linear, expanded at the 

 base. — Sower. Min. Conch, t. cccclxiv. f. 2. — London clay, Barton. 



3. B. elUptica — Elliptical, elongated, transversely striated ; vertex perfo- 

 rated ; aperture widest at the base — Sower. Min. Conch, t. cccclxiv. f. 6.— 

 London clay. Barton. 



4. B. attenuata. — Elliptical, transversely striated; superior portion elon- 

 gated, truncated, perforated ; aperture curved, widest towards the base ; striae 



distant in the middle — Sower. Min. Conch, t. cccclxiv. f. 3 London clay. 



Hordwell. 



5. B.filosa — A fragment. " Its numerous striae and expanded lip distin- 

 guish it from B. attenuata."— -Sozwr. Min. Conch, t. cccclxiv. f. 4. 



