CONTENTS. XI 



XI. 



THE FRESH-WATER MUSSEL. 



General structure Respiratory organs Alimentary organs Circulatory 

 system Excretory organs Reproductive organs Development Laboratory 



work. -; '. . . - - - ',' .... . p. 104 121. 



XII. 



THE FRESH-WATER CRAYFISH AND THE LOBSTER. 



Habitat General structure Appendages Segments Alimentary canal 

 Circulatory organs -Respiratory organs The Green glands Nervous system 

 Sense organs Reproductive organs Development Laboratory work. 



p.. 122 151. 

 XIII. 



THE FROG. 



General characters Development Specific characters of Rana tenvporaria 

 and R. esculenta The pleuroperitoneal cavity and the alimentary canal The 

 neural canal and the cerebro-spinal axis Objects seen on transverse sections 

 at various points Comparison with lobster The skeleton The digestive 

 system The blood and lymph vascular systems The ductless glands The 

 respiratory organs The urinary organs The generative organs The nervous 

 system The sense organs Laboratory work. . p. 152 257. 



APPENDIX . .p. 258. 



