INVEKTEBEATA 



of the Ctenophora— The formation of the tentacles of Callianira—The affinities 

 of the Ctenophora with other Coelenterata— The experimental embryology of 

 Coelenterata — The ancestral meaning of the Planula larva . • Page 53 



CHAPTEK V 



PLATYHELMINTHES 



TJie Polyclada the most primitive group of Platyhelminthes so far as their develop- 

 ment is concerned — Development of Planoeera inquilina as a type of the Polyclada 

 —The nature of spiral cleavage— Definition of cell-lineage and th'e nomenclature 

 employed — MuUer's larva in the development of Yungia and its metamorphosis — 

 The interpretation of Mtiller's larva and the light which it throws on the 

 ancestral history of Platyhelminthes . . . • • Page 102 



CHAPTER VI 



NEMERTINEA 



The development of Cerebratiilus lacteus as a type of the Nemertinea — The Pilidiuni 

 larva and its metamorphosis — Experimental embryology of the Nemertinea — The 

 interpretation of the Pilidium larva and the light which it throws on the 

 ancestral history of Nemertinea ..... Page 118 



CHAPTER VII 



ANNELIDA 



Methods of preserving and mounting the eggs of Annelida — The development of 

 Pohjgordius appendiculatus as a type of the Annelida: its cell - lineage : its 

 Trochophore larva and the metamorphosis thereof — The Troohophore larva of 

 Pohjgordius lacteus and its metamorphosis — The development of various 

 Polyohaeta — The development of the nephridia of Criodrilus—The development 

 of Nephelis as a type of the Hirudiuea — The development of Clepsine — The inter- 

 Iiretation of the Trochophore larva and the ancestry of the Annelida . Page 128 



CHAPTER VIII 

 ARTHEOPODA 



Tlie development of Peripatus capensis as a type of the Prototracheata — The develop- 

 ment of Astacus as a type of the Crustacea' — The formation of layers in HoTnarus, 

 Lucifer, and Euphausia as types of the Eucarida-^The formation of layers in 

 Mysis as a type of the Peracarida— The formation of layers in Polyphemus and 

 Branchipus as types of the Cladocera — The formation of layers in Lepas as a type 

 of the Girripedia — The larval history of Cyclops as a type of Cnistacean larval 

 history : the Nauplius and Metanauplius larval stages — The larval history of 

 Phyllopoda : the Nauplius larva of Apus and Branchipus — The larval history of 



Cirripedia : the Nauplius and Pupa .stages — The larval history of Ostracoda 



The larval history of Enphausidacea and Penaeidea : the Nauplius, Protozoaea, and 



