Bull. U. S. F. C. 1897. (To face page 426.) 
Plate XVIII. 
LARGE BAROQUE PEARLS; IRREGULAR NACREOUS GROWTHS, WITH MORE OR LESS BEAUTY OF LUSTER AND COLOR. 
Nos. 1, 7, 8. 11. Showing a twisted structure. No. 12. With a row of protuberances. 
Nos. 2, 3, 4, 6, 10. More regular. No. 9. immense mass of hinge-matter, salmon-pink in color. 
The lower group is the 
ir group. 
