xiv CONTENTS 



PAGE 



Phylum Protozoa — cuntinued. 



Class V. Infusoria 88 



1. Example of the Class— ParamcBOwim caudaium . . 88 



2. Classification and General Organisation . . 91 

 Systematic Position of the Example . . 91 

 Further Remarks on the Protozoa .101 



SECTION III 



Phylum and Class Porifera [Parazoa] . ... 105 



1. Example of the Class— /Si/con gelatinosum . . . . 105 



2. Distinctive Characters and Classification . Ill 

 Systematic Position of the Example . . 112 



.3. General Organisation . . 114 



SECTION IV 



Phylum Ccelenterata . . ... 128 



Class I. Hydrozoa .... .128 



1. Example of the Class — Obelia . 128 



2. General Structure and Classification . 140 

 Systematic Position of the Example 142 

 Additional Remarks . . . . 167 



Class II. Scyphozoa 168 



1. Example of the Class — Aurelia auritu . 168 



2. General Structure and Classification . 176 

 Systematic Position of the Example . . . 177 

 Additional Remarks .... . 184 



Class III. Actinozoa .185 



1. Example of the Class — Tealni, crassicornis . 185 



2.' Distinctive-Characters and Classification . 193 



Systematic Position of the Example . 196 



3. General Organisation ... . 196 

 Class IV. Ctenophora . .... .211 



1. Example of the Class — Hoiiinphora plumosa . . 211 



2. Distinctive Characters and Classification . . 220 

 Systematic Position of the Example . . 221 



3. General Organisation ... ... 222 



Appendix to Ctenophora— Gteno^dana and Codoplana . 225 



The Relationships of the Ccelenterata . . 226 



Appendix (II) to the Ccelenterata — The Mesozoa . 230 



SECTION V 



Phylum Platyhelminthbs . . . . 235 



1. Examples of the Phylum . 236 



i. Planaria or Dendrocodum . . . 236 



ii. Fasciola hepatica . . ... . . 240 



iii. Tcenia solium . , . ... . 245 



