LIST OF ILLUSTRATIONS 



FIGURE PAGE 



56. Skeleton of Python Frontispiece 



36. Sperm of Fur Seal (After Oliver) 4 



37. "Young" Spermatid (After Ballowitz) 5 



38. Spermatid of Fur Seal (After Oliver) 5 



39. Spermatid of Fur Seal (After Oliver) 6 



40. Spermatid of Fur Seal (After Oliver) 8 



41. Spermatid of Fur Seal (After Oliver) . . . . . 8 



42. Development of Sperm of Argas Miniatus (After Casteel) 10, 11 



43. Development of an Ascidian Egg (After Conklin) ... 17 



44. Spinule Cell of Styela Yakutatensis (After Huntsman) . 44 



45. Spinule Cell of Styela Plicata (After Huntsman) ... 45 



46. Spinule Cell of Styela Greeleyi (After Huntsman) . . 46 



47. Spinule Cell of Styela Montereyensis (After Ritter and For- 



syth) 47 



48. Spicules of Sponges (After Lankester) 51 



49. 50, 51. Development of a Spicule (After Lankester) . 52, 53 



52. Trichomes of Papaver Orientale (After Cannon) ... 55 



53. Trichomes of P. Pilosum (After Cannon) .... 55 



54. Trichomes of P. Somniferum (After Cannon) .... 55 



55. Side View of Auiphioxus (After Parker & Haswell) . . 95 



57. Tentacle of Halocynthia Johnsoni (Schematic; After Ritter) 98 



58. Acacia Elata 99 



59. Vicia Gigantea 100 



60. Cassia Sp 100 



61. Sequoia Sempervirens 101 



XV 



