1 1 I / !" 



CONTENTS 



CHAP. PAGE 



I. Introductory \ 



II. On Magnitude 16 



III. The Rate of Growth ,50 



IV. On the Internal Form and Structure of the Cell . 156 



V. The Forms of Cells . 201 



VI. A Note on Adsorption 277 



VII. The Forms of Tissues, or Cell-aggregates . . . 293 



VIII. The same {continued) • . . 346 



IX. On Concretions, Spicules, and Spicular Skeletons . 411 



X. A Parenthetic Note on Geodetics .... 488 



XI. The Logarithmic Spiral 493 



XII. The Spiral Shells of the Foraminifera . . . 587 



XIII. The Shapes of Horns, and of Teeth or Tusks: with 



A Note on Torsion 612 



XIV. On Leaf-arrangement, or Phyllotaxis . . . 635 



XV. On the Shapes of Eggs, and of certain other Hollow 



Structures 652 



XVI. On Form and Mechanical Efficiency .... 670 



XVII. On the Theory of Transformations, or the Comparison 



OF Related Forms 719 



Epilogue 778 



Index 780 



/o'?i'a 



