CONTEXTS. 



XV 



CHAPTER XIV. Digits: Recapitulation 



CHAPTER XV. Minor Symmetries: Segments in Appendages 



CHAPTER XVI. Radial Series 



Coelenterata. Pedicellariae of Echinoderms. Cell-Division. 



CHAPTER XVII. Radial Series: Echinodermata 



CHAPTER XVIII. Bilateral Series 



CHAPTER XIX. 



Further Illustrations of the Relationship 

 between Right and Left Sides 



CHAPTER XX. Supernumerary Appendages in Secondary 



Symmetry 



Introductory. — The Evidence as to Insects. 



CHAPTER XXI. 



The Evidence 



CHAPTER XXII. 

 CHAPTER XXIII. 



CHAPTER XXIV. 

 CHAPTER XXV. 



Appendages in Secondary Symmetry . 

 as to Crustacea. 



Duplicity of Appendages in Arthropoda . 



Secondary Symmetry in Vertebrates. Re- 

 marks on the Significance of Repetition 

 in Secondary Symmetry : Units of Repe- 

 tition 



Double Monsters 



Concluding Reflexions 



PAGE 



400 

 410 

 423 



432 

 448 



4G3 

 474 



525 



539 



553 

 559 

 567 



INDEX OF SUBJECTS, p. 576. 



INDEX OF PERSONS, p. 593. 



