IX 



THE HISTORY AND SCOPE OF ZOOLOGY 



387 



Branch a. 

 HEMICHORDA 



Branch b. 

 UROCHORDA 



Branch c. 

 CEPHALOCHOKDA 



Class. 



Sole Genus Balanoglossus. 



Grade a. LARVALIA. 

 1. APPENDICULARLE. 

 Grade b. SACCATA. 



1. ASCIDIACEA. 



2. THALIAOEA. 



Sole Genus Amphioxus. 



Grade a. CYCLOSTOMA. 



1. MYXINOIDEA. 



2. PETROMYZONTIA. 

 Grade b. GNATHOSTOMA. 



Sub-Grade 1. BRANCHIATA 

 HETERODACTYLA. 



1. PISCES. 



2. DIPNOI. 

 Sub-Grade 2. BRANCHIATA 



PENTADACTYLA. 

 1. AMPHIBIA. 

 Sub-Grade 3. PENTADACTYLA 



LlPOBRANCHIA. 



Branch a. Monocondyla. 



1. REPTILIA. 



2. AVES. 



Branch b. Amphicondyla. 

 1. MAMMALIA. 



THE END 



OF THE 



UNIVERSITY 



OF 



Printed by R. & R. CLARK, Edinburgh. 



