320 PROCEEDINGS OF THE MALACOLOGICAL SOCtETT. 



and shows traces of disease in the interior, especially in the region 

 of the large adductor impression and along the pallial line. It is 

 on these impressions that the pearls, which are small and somewhat 

 lustreless, are situated. 



Geological age. — Late Tertiary. 



Locality. — Bahamas. 



Collection. — Manchester Museum (Sir William Rawson Coll.) 

 [L. 4700J. 



EXPLANATION OF PLATE XIV. 



Mytilus edulis, Linnseus. Post-Pliocene (Eaised Beach) : Uddevalla, Sweden. 

 Fig. A. Valves showing attached pearls of various shapes and sizes. 

 ,, B. Series of free pearls from same species. 



Inoceramus (?). Albian (found in the so-called Cambridge Greensand) : Cambridge. 

 Fig. C. Isolated pearl exhibiting growth layers on fractured surface. 



Inocermnus. Senonian (found in the Crag deposits) : near Orford Castle, Suffolk. 

 Fig. D. Three examples of pearls, one of which still retains a small portion of the 

 original shell. 



Ostrea edulis, Linnieus. Pliocene (Coralline Crag) : Eamsholt, Suffolk. 

 Fig. E. Upper valve of above species containing attached pearl. 

 All the figures are natural size. 



