PLATE 12 



Fig. 3. Cross-section of myelencephalon of 21.5 mm. embryo of 

 Lepisosteus osseus, showing "anlage" of myelencephalic gland. X 112. 



Fig. 4. Cross-section of myelencephalon of 55 mm. embryo of Lepi- 

 sosteus osseus, showing further development of myelencephalic gland. 

 X 85. 



ABBREVIATIONS 

 bas. art. basilar artery. 

 bl. sin. blood sinus. 

 cart. cartilage. 



conn. tiss. n. connective tissue network. 

 epend. ependyma. 

 eryth. erythrocytes. 

 med. medulla oblongata. 

 pig. pigment cell. 

 4th vent. fourth ventricle. 



[104] 



