PLATE 2 



EXPLANATION OF FKiURES 



5 Cyst invaginated by a vascular pial trabecula, forming a 'glomerulus' from 

 15 cm. stage of development. X 1500. 



6 Photomicrograph of peripheral portion of pineal body of 21 cm. stage, show- 

 ing several cysts and several vascular trabeculae, and the presence of an enormous 

 number of melanic granules. X 250. 



7 Transverse section of a small alveolus or cyst, showing the character of the 

 cells, the distribution of the melanic granules and the reticular (coagidated) con- 

 tent. X 1500. 



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