x CONTENTS 



PAGE 



Excretory Organ ; The Blood-vascular System ; The Odonto- 

 phore ; The Nervous System ; Euthyneurous and Strepto- 

 neurous Gastropoda ; The Eyes ; The Otocysts ; The 

 Reproductive Organs ; Development of Gastropoda ; The 

 Veliger Larva ; Larval Torsion .... 69-80 



CHAPTER XXII. 



The Arthropoda ; Crustacea ; Apus cancriformis ; External 

 Characters; Appendages; Mouth Parts; Antennce ; Ali- 

 mentary Tract ; Blood-vascular System ; Excretory Organs ; 

 Nervous System ; Syncerebrum ; Rarity of Males ; Partheno- 

 genesis ; Ovary and Testis ; Nauplius Larva ; Metanauplius ; 

 Ecdyses ; Development of Larva into Adult . . 90- 1 1 1 



CHAPTER XXIII. 



The Crayfish, Astacus fluviatilis; Cephalothorax and Abdomen; 

 Appendages ; Abdominal Limbs ; Thoracic Limbs ; Max- 

 illipedes ; Second Maxilla compared with Limbs of Apus ; 

 Antennas ; Alimentary Tract ; Gastric Mill ; Blood-vascular 

 System ; Gills ; Excretory Organs ; Nervous System ; 

 Leydig's Organs ; Eyes of Arthropods ; Ova and Sperma- 

 tozoa ; Segmentation of the Ovum ; Gastrulation and For- 

 mation of the Embryo ; Development of the Organs ; The 

 Young Crayfish . . . . .112-148 



CHAPTER XXIV. 



The Insecta, Periplaneta orientalis and Periplaneta americana ; 

 The Head and Mouth Parts ; The Thorax and Limbs ; The 

 Wings ; The Abdomen ; Alimentary Canal ; Malpighian 

 Tubes ; Blood- vascular System ; Fat- Body ; Respiratory 

 Organs ; Tracheae ; Nervous System ; Reproductive Organs ; 

 Egg Cases ; Segmentation and Development of the Ovum ; 

 Amnion and Serosa ; Mesoblastic Somites ; Embryonic 

 Appendages ; The Young Cockroach ; Metamorphosis in 

 other Insects ; Comparison of Arthropoda with Chsetopoda . 149-171 



CHAPTER XXV. 



The Cephalochorda, Amphioxus lanceolatus ; Myotomes ; Fins ; 

 Mouth, Anus, and Atriopore ; Atrium ; Gonads ; Alimen- 

 tary Canal ; Pharynx ; Gill -Slits ; Notochord ; Ccelom ; 

 Blood-vascular System ; Excretory System ; Nervous 

 System ; Neuropore ; Segmentation of the Ovum and 

 Formation of Blastula ; Gastrulation ; Development of 

 Nervous System ; Mesoblastic Somites ; Head Cavities ; 

 Larval Amphioxus ; Atrial Folds ; Myoccele ; Splanch- 

 nocoele ; Sc'.erotome ; Primitive Structure of Amphioxus ; 

 Chordata and Allied Forms . . ... . 172-202 



