ILLUSTRATIONS xiii 



Fig. . Page 



64. Location of organ-forming germinal areas on the embryonic disk 



of the chick. 119 



65. Corresponding early embryonic stages from a series of typical ver- 



tebrates. 121 



66. Similarity of external form and proportions in a small and large 



fish. 122 



67. Relations between total length and various linear dimensions in the 



fish, Anchovia brozvnii. 1 23 



68. External dimensions during the human fetal growth period. 1 24. 



69. Changes in the relative length of the various regions of the human 



spinal cord at different stages. 125 



70. Changes in the relative weight of the head in different species at 



various stages. 128 



71. Changes in the relative weight of the musculature in different 



species at various stages. 129 



72. Changes in the relative weight of the skeleton in different species 



at various stages. 13° 



73. Changes in the relative weight of the brain in different species at 



various stages. 1 3 1 



74. Changes in the relative weight of the viscera in different species at 



various stages. I 3 1 



75. Percentage growth in weight of the human body and viscera during 



fetal and postnatal life. 132 



76. Types of human postnatal growth. 1 34 



77. The thyroid gland of man. 1 52 



78. Typical untreated cretin. 153 



79. Artificial cretinism in sheep. 154 



80. A case due to hypothyroidism in adult life. 155 



81. Increase in the calcium content of the blood due to injections of 



parathyroid extract. 156 



82. Masculine form of a woman. 159 



83. The effect of artificial injections of ovarian hormone on the epi- 



thelium of the uterus. 160 



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