PLATE 8 



EXPLANATION OF FIGURES 



66 Photograph of the caudal regions of a male and a female brook lamprey, 

 showing the external sex characters. 



67 Microphotograph of a germ gland of a larva 47.5 mm. long, showing a cell 

 nest with dividing and resting cells. 



68 Section of the germ gland of a larva 54 mm. long, showing a cyst with 

 dividing cells on the left, cysts with cells in synizesis on the right, and several 

 growing oocytes. 



142 



