CONTENTS 



CONTENTS OF No. 265, N.S., AprU, 1923. 

 MEMOIRS : PAGE 



Some Observations upon the Development of the Teeth of Phy seter 

 macrocephalus. By Frank E. Beddard, D.Sc, M.A., F.R.S. 

 (With 13 Text-figures) 1 



The ' Segmentation Cavity ' of the Egg of the Frog. By Alexander 

 Meek. (With Plate 1 and 1 Text-figure) 33 



Nuclear Divisions in Amoeba proteus. By Monica Taylor, S.N.D. 

 (With Plate 2) 39 



■ On Amphilina paragonopora, sp.n., and a hitherto undescribed 

 Phase in the Life-historv of the Genus. By W. N. F. Woodland, 

 D.Sc. (London). (With Elates 3-5) 47 



On the Strobilization of Aurelia. By E. Percival, B.Sc, Department 

 of Zoology, The University, Leeds. (With Plate 6 and 3 Text-figures) 85 



Histology of the Soft Parts of Astraeid Corals. By G. Matthai, M.A. 

 (With Plates 7 and 8) 101 



The Yolk-Sac and Allantoic Placenta in Perameles. By T. Thomson 

 Flynn, D.Sc, Ralston Professor of Biology, University of Tasmania. 

 (With Plates 9-11 and 4 Text-figures) 123 



CONTENTS OF No. 266, N.S., July, 1923. 

 MEMOIRS : 



The Male Meiotic Phase in two Genera of Marsupials (Macropus and 

 Petauroides). By W. E. Agar, F.R.S. , Professor of Zoology in the 

 University of Melbourne. (With Plates 12-14) . . . .183 



Marsupial Spermatogenesis. By A. W. Greenwood, B.Sc, University 

 of Melbourne. (With Plates 15 and 16) 203 



On Sexual Difl:erentiation in the Infusoria. By Professor V. A. 

 DoGiEL, Zootomical Laboratory, University of Petrograd. (With 

 Plate 17 and 1 Text-figure) 219 



' Sanguinicola from the Sudan. By W. N. F. Woodland, Wellcome 



Bureau of Scientific Research. (With Plate 18) . . . . 233 



On Centropygus j o s e e n s i s , a Leech from Brazil, By Charles 

 Badham, B.Sc, M.B., Ch.M. (With 10 Text-figures) . . .243 



V Some Observations on the Hypophysis of Petromyzon and of Amia. 



By G. R. DE Beer, B.A., BcC. (With 34 Text-figures) . . .257 



The Relation of the form of a Sponge to its Currents. By G. P. Bidder 

 Sc.D. (With 12 Text-figures) 293 



