Simpson,George Gaylord <br/><br/>
Tempo and mode in evolution 

 - New York  Columbia university press  1944 
 - x, 237p : ill ; 23 cm 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Animals<br/>Sea Shells
<br/><br/><label>Universal Decimal Class. No.: </label>13  / JJ12