CONTENTS 



SECTION XIII 



PAGE 



PHYLUM CHORDATA 1 



lub-phylmn and Class I. Adelochorda ... . . . 1 



.b-phylum and Class II. TIrochorda H 



1. Example of the Class Ascidia 12 



'. Distinctive Characters and Classification 18 



hematic Position of the Example 20 



.ner-1 Organisation 20 



Sub-phylum III. Vertebrata 37 



Division A. ACRANIA 38 



,, B. CRANIATA . 58 



I. Cyclostomata 115 



1. Example of the Class Petromyzon llfi 



2. Distinctive Characters and Classification 128 



parison of the Myxinoids with the Lamprey .... 129 



4. General Remarks 132 



II. Pisces 134 



'lass I. Elasmobranchii 134 



IxM.mple of the Class Scyllium canicula or Chilosctfttwm 



fusciim ... . 135 



Distinctive^" and Classification 154 



organisation 157 



II. Holocephali 173 



