ILLUSTRATIONS 



1 John James Audubon, Frontispiece 



PAGE 



2 Alexander Wilson 21 



3 Rafinesque 29 



4 Lewis and Clark, Thomas Jefferson, Thomas Nuttall ... 35 



5 Louis Agassiz 38 



6 James Dwight Dana, Joseph Leidy, Edward Drinker Cope, 



Othniel Charles Marsh 41 



7 Asa Gray 43 



8 Spencer Fullerton Baird 44 



9 The Academy of Natural Sciences of Philadelphia .... 53 



10 The American Museum of Natural History in New York . 54 



11 Blue shark and school of young 55 



12 Duck hawk at nest 56 



13 Florida swamp 56 



14 Woolly rhinoceros, saiga antelope and mammoth .... 57 



15 Monarch butterfly 58 



16 New sources of aquatic food 60 



17 The U. S. National Museum 61 



18 The New York Botanical Gardens 64 



19 The laurel bank in the Arnold Arboretum 65 



20 The "forest primeval" in the Arnold Arboretum 66 



21 Marine Biological Laboratory at Woods Hole, Mass. ... 68 



22 View of Woods Hole 69 



23 Animal community of a New England wharf 70 



24 The Station for Experimental Evolution of the Carnegie In- 



stitution 74 



25 Desert Botanical Laboratory of the Carnegie Institution . . 75 



26 Old shore line of Salton Sea 78 



27 Tortugas Laboratory of the Carnegie Institution 82 



28 The yacht "Anton Dohrn" of the Carnegie Institution ... 83 



29 Types of Protozoa 90 



30 Types of Protozoa 91 



31 Lower plant life 93 



32 Amoeba proteus 94 



33 Life cycle of malarial organism 97 



34 Phlox, liverwort and moss 99 



35 Invertebrate types 102 



36 Vertebrate embryos . . . 104 



13 ' 



