Charles R. Stockard 513 
in Bdellostoma I have been impressed with the manner in which the 
history of the lens in these embryos seems to corroborate the conclusions 
drawn by the experimenters mentioned above. In a brief way I wish to 
‘present these points, which are readily interpreted in the hght of the 
Fic. 1. A section through the eye of a 15 mm. embryo of Bdellostoma. L, 
the lens at the height of its development, the contact between the optic-cup 
and the ectoderm has just been lost. 
Fic. 2. The eye of an older embryo, the lens, L, degenerating and the 
optic-cup well removed from the outer wali. 
Fic. 3. The eye of an old embryo in which the lens has entirely disap- 
peared. All camera drawings to the same scale. 
experiments, while they in turn also lend support to the experimental 
conclusions by showing that many of the conditions artificially pro- 
duced may occur in a normal embryo. 
