CONTENTS 



Introduction page 371 



Behaviour 37 2 



1. Introduction : Individuality in Siphonophores 372 



2. Behaviour of the float 37 2 



3. Behaviour of the tentacles 375 



4. The behaviour of the remaining appendages 376 



5. Co-ordination 377 



Histology 37^ 



1. Introduction: The Siphonophora compared with other Hydrozoa . 378 



2. Histological techniques 379 



3. The muscular system 3 &° 



4. The nervous system 3^ 2 



5. The mesogloea 3^5 



6. The gas-gland 39° 



7. Nematocysts 394 



8. Histology of the digestive regions 397 



Discussion 4°3 



Summary 4°3 



References 4°5 



