LIST OF ILLUSTRATIONS. XV 



FIG. PAGE 



67. Transverse section of the acusticum of the sturgeon to show 



acusticum cells and a Purkinje cell 134 



68. A section through the same region as in Fig. 67, to show cell 



forms intermediate between the acusticum and Purkinje cells. 136 



69. A diagram to show the central endings of the special cutaneous 



components in fishes 138 



70. A diagram to show the central ending of the vestibular and 



cochlear nerves and of the optic tract in man and the chief 

 secondary tracts related to them 140 



71. A, a section through the retina of a mouse embryo of 15 mm.; 



B, a section through the retina of a chick embryo of fourteen 

 days incubation; C, a section of the retina of a dog. From 

 Cajal 144 



72. Cells from the retina of the chicken. From Cajal 145 



73. The tectum opticum of the sturgeon 147 



74. A section of the optic lobe of a bird. From Cajal .... 149 



75. A series of diagrams intended to illustrate the origin and mode 



of formation of the optic vesicle in vertebrates 151 



76. A sketch showing the relations of the two epiphyses in verte- 



brates 152 



77. A diagrammatic representation of the general visceral sensory 



components in a trunk segment 155 



78. A transverse section through the region of Clarke's column of 



the thoracic cord of a new-born dog. From Cajal .... 156 



79. A reconstruction of the cranial nerve components in a tailed 



amphibian, Amblystoma. After Coghill 158 



80. A simple diagram of the visceral nerves of the head in fishes. 159 



81. Four transverse sections through the medulla oblongata of the 



frog to show the position and ending of the fasciculus com- 

 munis and nucleus commissuralis 160 



82. Transverse section through the medulla oblongata of a mouse 



at the level of the nucleus commissuralis. From Cajal . . 161 



83. Transverse section through the medulla oblongata of a mouse 



four days old. From Cajal 162 



84. A, a transverse section through the medulla oblongata of the 



sturgeon at the level of the X nerve; B, at the level of the 



IX nerve 163 



85. Sense organs of bony fishes. A, a taste bud from the oesopha- 



gus of Catostomus at the time of hatching; B, a taste bud 



