CONTENTS OF No. I81.-New Series. 



MEMOIRS : 



PAGE 



On a Free-swimming Hydroid, Pelagoliydra mirabilis, n. gen. et 

 sp. By Arthur Dendy, D.Sc, T.L.S., Professor of Biology in tlie 

 Canterbury College, University of New Zealand. ("With Plates 

 1 and 2) 1 



Studies in the Retina. Parts III, IV, and V, with Summary. By 

 Henry M. Bernard, M.A.Cantab. (Prom the Biological Labora- 

 tories of the Royal College of Science, Loudon). (With Plates 

 3—5) 25 



Notes on the Relations of the Krdneys in Haliotis tuberculata, 

 etc. By H. J. Fleure, B.Sc, U.C.W., Aberystwyth. ("With 

 Plate 6) 77 



Notes on the Development of Paludina vivipara, with special 

 reference to the Urino-genital Organs and Theories of Gasteropod 

 Torsion. By Isabella M. Drummond. (With Plates 7 — 9) . 97 



Is Chemotaxis a Factor in the Fertilisation of the Eggs of Animals ? 

 By A.. H. Reginald Buller, B.Sc, Ph.D., Demonstrator in 

 Botany at the University of Birmingham 145 



