VI PBEFAOE. 



Heilprin, in charge of the invertebrate palseontological collection 

 of the Academy of Natural Sciences of Philadelphia, 



Having made such large acknowledgments, it is proper to 

 acknowledge further that I cannot, on this occasion, properly 

 claim the title of author ; because there is very little herein con- 

 tained originating with myself. The work is mainly a compilation ; 

 yet the selection and arrangement of material have been guided 

 by experience, and if it should fail to realize reasonable expec- 

 tations the responsibility for such failure must rest with 



GEO. W. TRYON, Jr, 



Academy of Nat. Sciences, 



Philada., December, 1883. 



