PLATE 1 



EXPLANATION OF FIGURES 



1 Right pronephros of Bdellostoma no. 6, showing its position in the pericar- 

 dial cavity. Natural size. 



2 Left pronephros of Bdellostoma no. 6, showing position in the pericardial 

 cavity. Natural size. 



3 Right pronephros of Myxine no. 5, showing position in the pericardial 

 cavity. Natural size. 



4 Left pronephros of Myxine no. 5, showing position in the pericardial 

 cavity. X !§. 



5 Transverse section through the right pronephros of Bdellostoma no. 6. 

 Camera, X 25. 



• 7 Left pronephros of Bdellostoma no. 16. X 4. 



8 Left pronephros of Bdellostoma no. 18. X 4. 



9 Left pronephros of Bdellostoma no. 7. X 4. 



10 Right pronephros of Bdellostoma no. 16. X 4. 



11 Right pronephros of Bdellostoma no. IS. X 4. 



140 



