PLATE 5 



EXPLANATION OF FIGURES 



30 Longitudinal section through the central duct in pronephros of Myxine 

 no. n. Camera lucida, X 50. 



31 Longitudinal section through the central duct of- one of the youngest 

 specimens, Myxine no. 18. Camera, X 90. y^ 



32 Transverse section through pronephros of Myxine no. 10, showing the 

 central duct. Not all the tubules are included in the sketch. Camera lucida, 

 X 30. 



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

 central duct with its columnar walls intact. Camera lucida, X 50. 



34 Transverse section through pronephros of one of the youngest specimens. 

 Myxine no. 18, showing the central mass. Camera lucida, X 50. 



35 Longitudinal section through the central mass in pronephros of Myxine 

 no. 11. Camera lucida, X 90. 



148 



