CONTENTS vii 



Page 



Vegetative Propagation and Regeneration in Flat-Worms (Platy- 



helmia) — Flukes and Tapeworms. Planarian Worms — Microstoinum - - 329 



Vegetative Propagation and Regeneration in Bristle- Worms (CHjEto- 

 PODa) — Possible Meaning of Segmentation. Regenerative Powers. Chains 

 Formed by Budding. Lateral Budding of Syllis ramosa 329 



Vegetative Propagation and Regener.^tion in Moss-Polypes (Polyzoa) 

 — Formation of Colonies by Budding. External Winter-Buds, Internal Winter- 

 Buds (Statoblasts). Regenerative Powers - 330 



Vegetative Propagation and Regeneration in the Higher Groups of 

 Many-celled Animals (Metazoa) — Regenerative Powers of Molluscs, 

 Arthropods, and Vertebrates. Budding of Ascidians or Sea-Squirts (Urochorda) 331 



CHAPTER LIV.— ANIMAL DEVELOPMENT— PROPAGATION 

 BY MEANS OF EGGS 



Development from Eggs in Animalcules (Protozoa) — Origin of Many- 

 celled Animals (Metazoa) from Colonial Animalcules (Protozoa). Division 

 of Physiological Labour. Evolution of Tissues. Life-History of Volvox, a 

 Colonial Animalcule - 333 



Development of Eggs in Many-celled Animals (Metazoa)— Ontogeny and 

 Phylogeny. Preformation and Epigenesis. Polar Bodies. Law of Recapitu- 

 lation. Cleavage or Segmentation of the Embryo. The Blastula. Develop- 

 ment of the Freshwater Polype {Hydra). The Gastrula, — Gastrasa Theory. 

 Development of a Sponge. Development of the Lancelet {Amphioxus). In- 

 fluence of Food- Yolk on Development 335 



ANIMAL LIFE-HISTORIES— PROTECTION OF EGGS 

 AND YOUNG— ANIMAL DWELLINGS 



CHAPTER LV.— LIFE-HISTORIES, &c., OF BACKBONELESS 



ANIMALS (Invertebrata) 



Life-Histories, &c., of Zoophytes (Ccelenterata) — Alternation of Genera- 

 tions in Hydroid Zoophytes. Evolution of Jelly-Fishes (Medusae), and Stages 

 in their Degeneration. Life-History of Aurelia. Nursing of Eggs and 

 Embryos in Jelly-Fishes, Sea-Anemones, and Corals. The Planula Larva - 349 



Life-Histories, &c., of Hedgehog-skinned Animals (Echinodermata)— 

 Larval Forms. Life-History of Brittle-Stars (Pphiiiroidea): the Pluteus 

 Larva : Direct Development and Nursing of Embryos in certain Brittle-Stars 

 (e.g. Amphiura squamata). Pluteus Larva of Sea-Urchins {Echinoidea): 

 Nursing of Embryos in Hemiaster: Burrowing Sea-Urchins. Ordinary Star- 

 Fishes {Asteroidea): Bipinnaria and Brachiolaria Larvae: Nursing Arrange- 

 ments in Pterasterida and Leptoptychaster. Sea-Cucumbers (Holothuroidea) : 

 Auricularia Larva: Nursing of Embryos in Pj'(?/kj' i?//%z)>/zy^^ .... 354 



Life-Histories, &c., of Segmented Worms (Annelida) — Bristle-Worms 

 {Chcetopoda) — Care of Eggs in Scale-Worms (Polynoids), Autolytus prolifer. 



