FIGURE 1.53. SEGMENTATION OF A BONY FISH.

FIGURE 1.54. DISCOID GASTRULA OF A BONY FISH.

FIGURES 1.55 AND 1.56. SECTIONS OF BLASTULA OF SHARK.

FIGURE 1.57. DISCOID SEGMENTATION OF BIRD'S OVUM.

FIGURES 1.58 TO 1.61. GASTRULATION OF THE BIRD.

FIGURE 1.62. GERMINAL DISK OF THE LIZARD.

FIGURES 1.63 AND 1.64. GASTRULATION OF THE OPOSSUM.

FIGURES 1.65 TO 1.67. GASTRULATION OF THE OPOSSUM.

FIGURES 1.68 TO 1.71. GASTRULATION OF THE RABBIT.

FIGURE 1.72. GASTRULA OF THE PLACENTAL MAMMAL.

FIGURE 1.73. GASTRULA OF THE RABBIT.

FIGURES 1.74 AND 1.75. DIAGRAM OF THE FOUR SECONDARY GERMINAL LAYERS.

FIGURES 1.76 AND 1.77. COELOMULA OF SAGITTA.

FIGURE 1.78. SECTION OF YOUNG SAGITTA.

FIGURES 1.79 AND 1.80. SECTION OF AMPHIOXUS-LARVAE.