138 BYRNES. 
EXPLANATION OF PLATE XI. 
(All outlines traced with the camera.) 
Fics. 19 and 20. Two cross-sections through the posterior limb-region of 
a tadpole killed four days after injury. Fig. 19 is more posterior than Fig. 20. Both 
show the ventral edge of the right myotome destroyed ; also the posterior abdomi- 
nal muscle-rudiment. The limb-rudiments are present and uninjured. 
Fics. 21-25 show a series of cross-sections taken through the posterior part of 
the body of a tadpole killed twenty-six days after injury. Fig. 21 is a section 
through the posterior limb. The right myotome is reduced and does not come 
in contact with the limb. Figs. 23-25 show the regenerated posterior abdominal 
muscle-rudiment. 
Fics. 26-28. Series of cross-sections through the posterior part of the body 
of an injured tadpole, showing the normal limbs, the reduced myotomes, and the 
regenerating posterior abdominal muscle-rudiment. 
Fics. 29-35 show cross-sections through the posterior limb-region of a tadpole 
killed thirty-four days after injury. The limb-rudiments are normal and of equal 
size. The myotome-derivatives are entirely wanting throughout the limb-region. 
Fic. 36 shows a section through the same embryo, but taken in front of the 
posterior limb-region. The posterior abdominal muscle‘is just beginning to form, 
but is greatly reduced. 
