LIST OF ILLUSTRATIONS. 



FIG. 



1. Pineal eye of lizard {Hatteria) (after Spencer) . 



2. Pineal eye of lizard, in section (after Spencer) 



3. Head of horned toad {F/irynosoma) (after nature, by 



W. S. Atkinson) 



4. Conjugation of Infusoria (after Leuckart) 



5. Karyokinesis of cell (after Driiner) .... 



6. Reduction of chromatin in egg-cleavage (after Boveri) 



7. Development of Pandorina (after Pringsheim) 



8. Colony of Eudorina with antherozooids (after Goebel) 



9. Diagram of development of spermatozoa (after Boveri) 



10. Fertilization of egg (after Boveri) .... 



11. Reduction of chromosomes in developing egg (after 



Brauer). ........ 



12. Maturation of egg of Cyclops (after Riickert) . 



13. Larva of Echinus (after Boveri) .... 



14. Hybrid larva of Echinus and Sphcerechinus (after Boveri 



15. The arctic birch (after nature, by Anne L. Brown) . 



16. Skeleton of greenling {Hexagi-ammos) (after nature, by 



W. S. Atkinson) 



17. Skeleton of scarlet rock-fish {Sebastodes) (after nature, by 



W. S. Atkinson) 



18. Skeleton of angel fish {Angelichthys) (after nature, by 



W. S. Atkinson) 



19. Sacculina after leaving the egg (after Lang) . 



20. Sacculina attaching itself (after Lang) 



21. Sacculina, an early stage (after Lang) 



22. Sacculina after absorption of limbs (after Lang) 



23. Adult Sacculina attached to crab (after Lang) . 



2 xvii 



FAGB 

 34 



34 



35 

 92 



155 

 160 



165 

 167 

 172 



174 



180 

 182 



187 

 189 

 209 



224 



224 



225 

 279 

 280 

 280 

 280 

 281 



