X LIST OF ILLUSTRATIONS. 



29. Group of Hydractinia eckinata, with gonophores, . . 105 



30. Trophosome of Clytia Johnstoni, . . . ' . 108 



31. Free Medusoid of Clytia Johnstoni, . . . . . 109 



32. Development of A urelia, . . . " .no 



33. Generative zooid of Chrysaora, . " . . . . in 



34. Bean Aphis, . . . ... . 114 



35. Male organs and pollen of Flowering Plants, . . .121 



36. Female organs of Flowering Plants, . . . .122 



37. Fructifying Frond, Spore- cases, Spore, and Prothallus of a 



Fern .125 



38. Molecules and bacteria of organic infusions, . . 128 



39. Ideal section of the Crust of the Earth, . . . . 153 



