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“I 
PLATE 1 
EXPLANATION OF FIGURES 
Glycogenated nerve cells of Amphioxus. 
Nerve cells of Ammocoetes from the brain opposite the eye and ear. 
Nerve cells in the myel (medulla spinalis) of Ammocoetes with glycogen; 
also glycogen and fat in the same cells. 
Retina of an adult Petromyzon showing glycogen in the retinal nerve 
cells, and the decussation of the optic fibers. 
(a) Edge view of glycogenated retinal nerve cells. 
(b) Face view of retinal nerve cells. 
Ova of Petromyzon and Amblystoma (be) showing the great amount 
of glycogen in the cells of the animal pole. In the developing nervous 
system there is much glycogen. 
Lumbar enlargement of a ten day chick’s medulla spinalis showing a 
prismatic mass of glycogenated cells in the raphé. A similar glycogen- 
ated area is present in the medulla oblongata. 
Spinal ganglion of a 12 mm. pig embryo with glycogenated cells. (a) 
Some of the cells greatly enlarged. 
Glycogenated nerve trunks of the brachial plexus of a 30 mm. pig 
embryo. 
Glycogenated endymal cells of the brain plexuses in a cat embryo. (a) 
Endymal cells greatly enlarged. 
Choroid plexus of a 19 em. human embryo. (ab) Section through 
the cerebrum and medulla of a 35 mm. human embryo to show the 
glycogenated choroid plexus and the cells of the raphé in the medulla. 
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