1. To our subscribers

   • M. Jeuken

   Announcement Pages: 85 - 85

2. F. J. J. Buytendijk's contribution to animal behaviour: Animal psychology or ethology?

   • G. Thines
   • R. Zayan

   OriginalPaper Pages: 86 - 99

3. Niche, habitat, and related ecological concepts

   • M. Rejmánek
   • J. Jeník

   OriginalPaper Pages: 100 - 107

4. Stochastic development of cell populations under non-homogeneous conditions

   • MiloŠ Jílek

   OriginalPaper Pages: 108 - 119

5. On the theories of gene regulation and differentiation in eukaryotes

   • Nejat Düzgüneş

   OriginalPaper Pages: 120 - 126

6. The logomotor behavior of the nurse shark,Ginglymostoma cirratum; A time series analysis

   • J. H. Matis
   • H. Kleerekoper
   • D. Gruber

   OriginalPaper Pages: 127 - 135

7. Lenkende und Limitierende Faktoren in der Evolution

   • Wolf -Ernst Reif

   OriginalPaper Pages: 136 - 162

8. Some comments on “Reduction”

   • W. J. Van Der Steen

   OriginalPaper Pages: 163 - 167

9. Reviews

   • W. Van Laar
   • K. Kortmulder
   • A. Quispel

   BookReview Pages: 168 - 175

10. The genetic code and the origin of life

    • C. Portelli

    Letter to the Editor Pages: 176 - 177

11. New acquisitions of our library

    Legacy Pages: 178 - 180