XVI 



ILLUSTRATIONS 



Figure 



59. Vertical section through a fertile leaf of a Fern, Nephrodium 

 After Krug. 



GO. Younf; plant of Maidenhair Fern still attached to prothallus 



After Sachs. 



Gl. Sexual organs of a Fern, Polypodium vulgare 



G2. Longitudinal section through a nucellus 

 After Darwin. 



G3. Pollen-grains germinating on the stigma of a Grass 

 After Kerner. 



G-1. Ovary of Polygonum convolvulus during fertilization 



After Strasburger. 



65. A Dogfish and egg, Scyllium canicula . 

 From Day. 



06. Amphioxus lanceolatus ..... 

 After Lancaster. 



67. A Lung-fish, Ceratodus forsteri 

 After E. S. Goodrich. 



68. Tadpoles ....... 



Latter's Natural History of some Common Animals. 



69. Side view of Cypris Candida .... 

 After Zenker. 



70. The Apple Aphis, Aphis pomi 

 Carpenter's Life Story of Inserts. 



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