xvi LIST OF ILLUSTRATIONS 



PAGE 



29. Human Ear Modeled and Drawn by Mr. Woolner . . . 155 



30. Foetus of an Orang 156 



31. Vestigial Characters or Human Ears 157 



T^2. Hair Tracts ON THE Arms AND Hands OF Man 159 



2)T). Molar Teeth of Lower Jaw in Gorilla, Orang, and Man . 161 



34. Perforations of the Humerus in Three Species of Quad- 



rumana 162 



35. First Stages in the Embryonic Development of the Pond 



Snail, Lymnaeus 166 



36. Stages IN THE Development OT THE Vrawn, Peneus potimirium 170 



37. Later Stages in the Development of the Prawn, Peneus 



potimirium 170 



38. Metamorphosis OF A Barnacle, Ze^aj 171 



39. Embryos in Corresponding Stage of Development of 



Shark, Fowl, and Man 177 



40. Three Aquatic Types of Vertebrate, to Illustrate Con- 



vergent Adaptation 193 



41. Fierasfer acus, penetrating the Anal Openings of Holo- 



THURIANS 199 



42. Kallima, the "Dead-Leaf Butterfly" 202 



43. Diagram of a Cell, Showing Various Parts 291 



44. Diagram Showing Representative Stages in Mitotic or 



Indirect Cell-Division 292 



45. Germ Cell Set Apart in the Eight-Celled Stage of Cleav- 



age IN M last or americana 295 



46. Chromosomes of the Mosquito and of the Fruit Fly . . 297 



47. Diagram to Illustrate Spermatogenesis 298 



48. Diagram to Illustrate Oogenesis 299 



49. Diagram Showing the Parallel between Maturation of 



THE Sperm Cell and Maturation of the Ovum .... 300 



50. Diagram to Illustrate Fertilization 302 



51. Variation in Sedum spectahile Due to Differences in Colo?l 



of Light 313 



52. Temperature Phases of the Diurnal Peacock-Butterfly . 314 



53. Morphological Cycle OF Head Height IN fl'>'a/o(/a/>/fma. . 315 



54. Schematic Curves of Head Height in Hyalodaphnia as 



Grown IN Media OF Three Different Food Values . . 316 



55. Climatic Effects UPON Plumage IN Pigeons 317 



56. Effects of Injections into Ovary of Scrophularia. . . . 319 



