1844.] 



309 



a. Bulla Mortoni. 

 h. Natica. 

 c. Tornatella. 



4. Bulla Mortoni (a). (Cast.) Ovate, inflated, resembling in 

 form B. hydatis, spire concealed, surface spirally furrowed, the 

 furrows bearing traces of punctation. 



5. Natica (b). (Cast.) Of a small globular species with a deeply 

 channelled suture, spirally sulcated, and obsoletely reticulated 

 whorls and depressed spire. Locality, New Jersey. 



6. Tornatella (c), (Cast.) Oblong, bearing traces of spiral 

 striee ; spire exserted, subdeprcssed ; sides of body -whorl some- 

 what flattened ; columella perforate ; aperture lanceolate. Locality, 

 New Jersey. Allied to T. hullata of Morton, which, however, is 

 a much more ventricose species. 



Casts of Voluta. 



7. Voluta. (Casts.) a. Shell linear, lanceolate, whorls smooth. 

 h, Shell ovate, whorls smooth, c. Shell ovate, whorls angular 

 above, distant ribs. 



2Vb<e. — The figures are all of the natural size, except the Ostrea, which is 

 two-thirds in linear dimensions. 



2. List of Species common to the American and European Cre- 

 taceous Systems. 



Ostrea larva (O. falcata M.) 



vesicularis 



Gryphoea costata 



Pecten quinque-costatus 

 Belemnites mucronatus 



