202 CHOKDATA 



these differences in mind we shall briefly discuss one class 

 of the Chordata and then pass to the better-known verte- 

 brates. 



CLASSIFICATION OF THE CHORDATA 



BitANCH XII — Chordata. 



Sub-branch — Urochorda. 



Class — Urochorda or Tunicata. 

 Order — Ascidiacea. 

 Type of Order. 



Ascidia species — Sea squirt. 

 Sub-branch — Vertebrata. 

 Division A — Acrania. 

 Class — Acrania. 

 Type of Class. 



Amphioxus lanceolatus — Lancelet. 

 Division B^ — Craniata. 



Class I — Cyclostomata. 

 Type of Class, 



Petromyzon marinus — Lamprey. 

 Class II — Pisces. 

 Type of Class. 



Perca flavescens — Perch. 

 Class III — Amphibia. 

 Type of Class. 



Bufo lentiginosus — Toad. 

 Class IV — Reptilia. 

 Type of Class. 



Crotalus horridus — Rattlesnake. 

 Class V — Aves. 

 Type of Class. 



Passer domesticus — Sparrow. 

 Class VI — MammaUa. 

 Type of Class. 



Lepus sylvaticus — Rabbit. 



