CONTENTS OP No. 268 —New Series. 



MEMOIRS : page 



The Cleavage of the Egg- of Lepidosiren paradoxa. By Agnes E. 

 Miller, M.A., Department of Zoology, University of Glasgow. 

 (With 12 Text-iigures) 497 



The Morphology of the Nudibranchiate Mollusc Melibe (syn. Chioraera 

 leonina Gould, By H. P. Kjerschow Agersborg, B.S., M.S., M.A., 

 Ph.D., Williams College, Williamstown, Massachusetts. (With Plates 

 27 to 37) 507 



Observations upon the Behaviour and Structure of Hydra, By Sheina 

 Marshall, B.Sc, Assistant Naturalist, Scottish Marine Biological 

 Station, Millport. (With 4 Text-figures) 593 



Head Length Dimorphism of Mammalian Spermatozoa. By A. S. Parkes, 

 B.A. (Cantab.), Department of Zoology, University of Manchester. 

 (With 3Text-figures) 617 



On Brinkmann's System of the Nemertea Enopla and Siboganemertes 

 Weberi, n.g. n. sp. By Dr. Gerarda Stiasny-Wijnhopf. (With 

 26 Text-figures) 627 



Mr. Milford, Oxprd University Pr^ss, London, E.G. 4, will he glad to receive offers 

 for hack nurnbers of the Quarterly Journal of Microscopical Science. 



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