PTEEOBEANCHIA. 

 CEPHALODISCUS. 



By W. G. RIDEWOOD, D.Sc, Lecturer on Biology at St. Mary's 

 Medical School, University of London. 



CONTENTS. 



Introduction ........ 



Diagnosis of a New Species of Cephalodisctis {C. hodgsoni) 



Consideration of the Characters serviceable for the Discrimination of the 



Review of the six Species of Cephalodiscus . 



Key to the Identification of the Species of Cephalodiscus 



Relations between Rhabdo2Jleura and Cqihalodiscus 



Description of G. nigrescens — 



Material 



Tubarium . 



Polypides . 



Buccal Shield 



Post-oral Lamella 



Plumes 



Stolon 



Coelom 



General Internal Structure 



Collar Canal Muscle 



Alimentary Canal 



Gonads 



Buds and Budding 

 Description of G. hodgsoni — 



Material 



Tubarium . 



Polypides . 



Buccal Shield 



Plumes 



Post-oral Lamella 



Gonads 



Stolon and Budding 



Buds 

 Summary of Results . 

 Literature on Geplialodiscvs 

 Explanation of the Plates . 



Specie: 



s of Gephalodiscus 



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