CONTENTS 



SECTION XIII 



PHYLUM CHORDATA . 



Sub-phylum and Class I. Hemichorda (Adelochorda) 



Sub-phylum and Class II. Urochorda .... 



1. Example of the Class Ascidia . 



2. Distinctive Characters and Classification . 

 Systematic Position of the Example . 



3. General Organisation 



PAGE 

 1 



13 



14 



20 

 23 

 23 



Sub-phylum III. Euchorda . 

 Section I. ACRANIA . 

 Section II. CRANIATA 



42 

 43 

 63 



Class I. Cyclostomata . 



1. Example of the Class Petromyzon . 



2. Distinctive Characters and Classification . 



3. Comparison of the Myxinoids with the Lamprey 



4. General Remarks . 



119 

 119 

 133 

 134 



138 



Class II. Pisces 

 Sub-class I. Elasmobranchii 



2. Distinctive Characters and Classification 



3. General Organisation .... 



139 

 140 



1. Example of the^Sub-class -ScyHium canicula or Hemiscyllium 



mode stum ... 140 



161 



165 



V 



