PREFACE. 



Although the works of M.M. Edwards and Comte are the chief sources 

 from which the materials of these Piimers have been derived, others have 

 been freely used, and the classification and arrangement of the great Cuvier, 

 have been strictly adhered to. 



With the view of assisting the student in understanding and remem- 

 bering the systematic names, their etymologies have been added in the 

 Glossary. And, in as much as all persons who are desirous of studying 

 Natural History, are not acquainted with the Latin and Greek languages, 

 the words from the latter have been given in italics, in preference to 

 using the proper Greek characters, and the omega, where it occurs, has 

 been designated thus, 6. 



It is not designed that the questions at the foot of the page shall be 

 answered by repeating the text from memory; the pupil should be able 

 to give the facts in his o\vn language, and show he understands the 

 subject. 



The Plates were engraved by Mr. G. Thomas, No. 37 South Third 

 Street, Philadelphia. 



Philadelphia, April 15th, 1842. 



