xu CONTENTS 



CHAPTEK IV. 

 The Leech. Hirudo med/icinalis. 



PAGE 



External characters — Dissection — Examination of transverse sec- 

 tions 37 



CHAPTER V. 

 The Earthworm. Lumbricus terreatris. 



External characters — Dissection — Examination of transverse sec- 

 tions 56 



CHAPTER VI. 

 The Freshwater Mussel. Anodonta cygnea. 



The shell — Dissection of the mussel — Examination of transverse 

 sections ... .... . 76 



CHAPTER VII. 



The Edible Snail. HeUx pomatia. 



External characters — Dissectidft of the snail 103 



CHAPTER VIII. 

 The Crayfish. Aatacus flwviatil/is. 



External characters — Dissection — The arteries as seen in an in- 

 jected specimen 125 



CHAPTER IX. 



The Cockroach. Peripla/neta Americana. 



Habits — External characters— Dissection 153 



