XIV 



CONTENTS 



3- 



4- 



5- 

 6. 



7- 



Class II. Ophiuroidea — Brittle Stars 

 Class III. Echinoidea — Sea Urchins 

 Class IV. Holothurioidea — Sea Cucumbers 

 Class V. Crinoidea — Sea-lilies or Feather-stars 

 Development of Echinoderms .... 



8. Artificial Parthenogenesis .... 



9. The Position of Echinoderms in the Animal Kingdom 



PAGE 

 199 

 202 

 205 

 208 

 2IO 

 212 

 213 



CHAPTER XII 



Phylum Mollusca 242 



1. The Pearly Fresh-water Mussel — Anodonta and the 



Uniones ......... 243 



2. Class I. Amphineura .251 



3. Class II. Gastropoda . . . « . . . . ' 252 



a, A Land-snail, 253 ; b, Gastropoda in General, 258. 



4. Class III. Scaphopoda 261 



5. Class IV. Pelecypoda 261 



6. Class V. Cephalopoda ....... 264 



a, The Common Squid — Loligo, 264 ; b, Cephalopoda 

 in General, 267. 



7. Mollusca in General 269 



CHAPTER XIII 



Phylum Arthropoda . . . . . . . . 274 



1. Introduction 274 



