98 CONTRIBUTIONS 



I am not aware of this genus having been found in 

 a fossil state in Great Britain. M. Deshayes gives us three 

 for the Tertiary on the continent. Dr Morton has observed 

 one, C. costata, in the Tertiary of St Mary's, Maryland, 

 and Mr Conrad obtained two in the Upper Marine Forma- 

 tion of Maryland, viz. the convexa and glauca, both of 

 which Mr Say obtained in a living state on our coast. 

 Mr Conrad has also described a species, the lirata, from 

 Claiborne. 



FAMILY BULL^SANA. 



GENUS BULLA. Linnaus. 



B. St JMam.* Plate 4. Fig. 78. 



Description, Shell cylindrical, transversely striate ; sub- 

 stance of the shell rather thick ; spire truncate and umbi- 

 licate ; whorls somewhat compressed in the middle ; co- 

 lumella thickened at the base ; mouth linear, wider at the 

 base ; outer lip sharp. 



Length .7, Breadth 5-20ths, of an inch. 



Observations. This species resembles the figure of Sow- 

 erby's constricta.^ Ours is wider at the base, and the base 



* Named after the enlightened traveller and naturalist Geoffrey St 

 Hillaire. 

 t Min. Conch, plate 464, fig. 2. 



