X TABLE OF CONTENTS. 



PAGE 



LAMELLIBRANCHIATA. 



24. Shell of Fresh-water Mussel, Anodonta cygnea . . . .124 



25. General external features of same 128 



26. Viscera in situ of same . . . . . . . .132 



27. Nervous system of same . . . . . . . 135 



INSECTA. 



28. Common Cockroach, Periplaneta orientalis . . . . .138 



29. Larva of Privet Hawk Moth, Sphinx Ligustri . . . . 147 



30. Pupa of same 152 



31. Imago, male and female, of same . ...... 156 



CRUSTACEA. 



32. Common Crayfish, Astacus flwiatilis, female . . . . 162 



33. The same bisected, male 177 



34. Heart and vessels of same . . . . . . . .179 



35. Digestive, reproductive, and respiratory organs of same . . . 181 



36. Nervous system of same ........ 187 



ASTEROIDEA. 



- 37. Common Starfish, Asterias rubens, dried . . . . .190 



38. Digestive and motor organs of same 195 



CHAETOPODA. 



39. Common Earthworm, Lumbricus terrestris . . . . .196 



40. Digestive, reproductive, and circulatory organs of same . . .201 



41. Nervous system of same 209 



HlRUDINEA. 



42. Medicinal Leech, Hirudo medicinalis . . . . . .212 



43. Digestive organs of same . . . . . . . .216 



44. Nervous system of same . . . . . . . .219 



45. Reproductive and excretory organs of same . . . . .221 



CESTODA. 



46. Tapeworm, Taenia serrata, and cysts of Cysticercus pisiformis . 224 



47. Cysticercus pisiformis, mounted for microscope . . . . 229 



POLYZOA. 



48. Broad-leafed Horn wrack, Flustra foliacea . . . . .234 



ANTHOZOA. 



49. Sea Anemone, Tealia crassicornis ...... 239 



HYDROZOA. 



50. Sea-Fir, Sertularia abietina ; Medusa 245 



PORIFERA. 



51. Fresh-water Sponge, SpongilZa lacustris ; Euspongia officinalis . 249 



INFUSORIA AND AMOEBINA. 



52. Infusorian, Paramecium Aurelia and Amoeba Proteus . . . 254 



