Orr, Robert T.,  1908- <br/><br/>
Vertebrate biology / 
Robert T. Orr 
 - 5th ed 
 - Philadelphia :  Saunders College Publishing,  1982. 
 - 568p. ill. 24cm 
<br/><br/>Includes bibliographies and index 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Vertebrates