A 



TREATISE ON ZOOLOGY 



EDITED BY 



E. BAY LANKESTER 



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



HON. FELLOW OK EXETER COLLEGE, OXFORD; DIRECTOR OF THE NATURAL HISTORV 

 DEPARTMENT* OF THE BRITISH MUSEUM 



PART V 



MOLLUSCA 



BY 



PAUL PELSENEER, D.Sc. 



Reprint A.ASHER & CO. Amsterdam 1964 



