CONTENTS OF No. 184.-New Series. 



MEMOIRS : 



PAGE 



The Movements and Reactions of Fresh-water Plauarians : a Study 

 in Animal Behaviour. By flAyMOND Peael, Ph.D., Instructor in 

 Zoology in the University of Michigan, Ann Arbor, Michigan, 

 U.S.A 509 -7||-, 



Ofl the Diplochorda. — Part IV. On the Central Complex of Cepliaifl- 

 dl>aus dodecalophus, McI. By A. T. Mastekman, M.A., 

 D.Sc, Lecturer on Zoology, School of Medicine, Edinburgh. (With 

 Plates 33, 33) 715 



On Hypurgon Skeati, a New Genus and Species of Compound 

 Ascidians. By Igerna B. J. Sollas, B.Sc.Lond. (With Plates 

 34,35) 729 



The Anatomy of Arenicola ass i mills, Ehlers, and of a New Variety 

 of the Species, with some Observations on the Post-larval Stages. 

 By J. H. AsHWORTH, D.Sc. (With Plates 36, 37). . • -737 



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Title, Contents, and Index. 



