CONTEXTS OF VOLUME II XIU 



Studies on the Cellular Basis of Morphogenesis in the Sea Urchin. 



By T. Gustafson ........ 497 



Cell Differentiation : A Problem in Selective Gene Activation 

 Through Self-Produced Micro-Environmental Differences of 

 Carbon Dioxide Tension. By W. F. Loomis . . . 509 



RXA Synthesis in the Nucleus and RNA Transfer to the Cyto- 

 plasm in Tetrahymena pyriformis. By D. M. Prescott . , 527 



Cell Division and Protein Synthesis. By Erik Zeuthen . . 537 



Structure and Function in Amoeboid Movement. By Robert D. 



Allen .......... 549 



Some Problems of Ciliary Structure and Ciliary Function. By 



Bjorn A. Afzelius ........ 557 



Specific Membrane Transport and its Adaptation 

 Chairman's Introduction. By Bernard D, Davis . . . 571 



Approaches to the Analysis of Specific Membrane Transport. By 



Peter Mitchell 581 



Protein Uptake by Pinocytosis in Amoebae : Studies on Ferritin and 



Methylated Ferritin. By V. T. Nachmias and J. M. ?vlarshall, Jr. 605 

 Comparative Study of Membrane Permeability. By E. Schoft'eniels 621 

 Active Transport and Membrane Expansion-Contraction Cycles. 



By R. J. Goldacre ........ 633 



Author Index ......... 645 



Subject Index ......... 657 



