TREATISE ON ZOOLOGY 



EDITED BY 



E. RAY LANKESTER 



M.A., LL.D., F.R.S. 



HON. FELLOW OK EXKTF.R C'OLLECE, OXFORD; DIRECTOR OF THK NATURAL HISTORV 

 DF.PARTMEXTS <IK TI1K BRITISH MUSEl'M 



PART V 



M L L U S C A 



BY 



PAUL PELSENEER, D.Sc. 



LONDON 



ADAM & CHARLES BLACK 

 190G 



