Xij LIST OF ILLUSTRATIONS 



FIGURE PAGE 



85. Notochordal tissue 72 



86. Transaction through the compact bony wall of a human meta- 



carpal bone .73 



87. Longitudinal section of ground bone from the shaft of the human 



femur 74 



88. Isolated bone cell shrunk away from wall of its lacuna . . 75 



89. An Haversian system, including the central canal, several lamellae, 



lacunae and canaliculi 75 



90. Transverse section of Haversian canal, with contents ... 76 

 91. The primary changes in intracartilaginous bone formation . . 80 

 92. A longitudinal section of the two distal phalanges from the finger 



of a five-months' human fetus 81 



93. Reconstruction of cartilage into bone 82 



94. Trabecula of primary enchondral bone, showing a central deep- 

 staining core of calcified cartilage and a peripheral layer of osteo- 



blasts 83 



95. Trabecula of primary bone from the finger of a human fetus . 84 



96. Intramembranous bone formation in the lower jaw of a sheep fetus 87 

 97. Smooth muscle cells . . . . . . . .91 



98. Smooth muscle cells from the pig's stomach .... 92 



99. Smooth muscle cells from the wall of the human intestine . . 92 

 100. Smooth muscle cells from the wall of the human intestine . . 93 

 101. Two stages in the histogenesis of smooth muscle, from the wall of 



the esophagus of a pig embryo 94 



102. A group of myoblasts from the heart muscle syncytium of a 48-hour 



chick embryo 95 



103. Cardiac muscle of guinea-pig, showing several branches, cross 



striations (ground membranes) and a number of intercalated disks 95 

 104. Cardiac muscle cells from the pig's heart, isolated in equal parts of 



alcohol, glycerin, and water ....... 96 



105. Cardiac muscle of the human heart; the abundant branches are 



plainly shown 97 



106. The central portion of the preceding figure, more highly magnified . 98 

 107. Transection of a group of cardiac muscle fibers from a papillary 



muscle of the human heart 98 



108. Developing muscle fibers from the heart of a human fetus at 



seven months 99 



109. Cardiac muscle fibers ........ 100 



110. Diagram of a striped muscle fiber, according to Heidenhain . . 101 

 111. Longitudinal section of portion of wing muscle fiber of Mantis at 



mid-phase of contraction ....... 101 



112. Longitudinal section of portion of atrio-ventricular bundle of heart 



of beef. Many of the cells are binuclented .... 102 



