1902 - 3 .] Mr John Cameron on the Pineal Body. 581 
frog, and of these the left is somewhat the larger of the two. 
Note that the nuclei around the recesses are more deeply stained 
than the adjoining nuclei. The right recess is somewhat obscured 
with pigment. Embryo No. 15. 
Eig. 4 is from an older toad-tadpole, and shows the evagination 
as situated to the left of the mesial plane. The fact that the 
deeply-stained nuclei are now all accumulated around this out- 
growth shows that it has been formed by the blending of the two 
primary recesses. Embryo No. 17 (5 mm. long; eleven days after 
fertilisation). 
Eig. 5 is drawn from a toad-tadpole (10 mm. long; twenty days 
after fertilisation), and shows the epiphysial evagination placed 
most distinctly to the left of the mesial plane. The pigment is 
seen to have entirely disappeared. Embryo No. 26. 
Eig. 6 is a transverse section of the roof of a newt-tadpole’s 
fore-brain (5*5 mm. long; eleven days after fertilisation). The 
epiphysial outgrowth is placed to the left of the mesial plane. 
There is no pigment present in the brain at this stage. Embryo 
No. 27. 
Eig. 7 is from an older newt-tadpole (twenty days after fertilisa- 
tion ; 1 1 mm. long). The epiphysial opening is to the left of the 
mesial plane. Embryo No. 34. 
Fig. 8 is drawn from a frog-tadpole (fifty-one days after fertilisa- 
tion ; 30 mm. long). The epiphysial opening is shown to the left 
of the mesial plane. Embryo No. 14. 
(. Issued separately December 28 , 1903 .) 
