PLATE 4 



:XPLANATION OF FIGURES 



24 Transverse section through a pronephric tubule of Myxine no. 11, showing 

 connective tissue. 



25 Section through some tubules of pronephros of Myxine no. 15, showing the 

 large amount of connective tissue around the tubules. 



26 Transverse section through a pronephric tubule of Myxine no. 10, showing 

 blood sinus around the tubule. 



27 Transverse section through some tubules of pronephros of Myxine no. 

 10, showing difference in size of the tubules. 



28 Transverse section through pronephros of Myxine no. 11, showing the 

 central duct in the central mass. 



29 Transverse section through pronephros of Myxine no. 11, showing central 

 duct in communication with the pronephric vein. Camera lucida, X 50. 



146 



