Independent Development of the Lens. 401 
than the lens in the eye on the other side, yet this bud shows dis- 
tinct lens character. 
A perfect lens is seen in fig. 2, plate I, to be entirely separated 
from the brain and no optic cup exists. Fig. 13 shows a lens in 
a small choroid cup and a second free lens lying near. Fig 7 
illustrates a similar case. Figs 8 and 12 show extremely anterior 
lensesin eyeless individuals and again fig. 5and fig. 3, plate II, show 
two beautiful lateral lensesin another eyelessspecimen. Fig.6shows 
a section with three well differentiated lenses all free from contact 
with an optic vesicle; a more posterior section of this embryo, 
fig. 27 shows a choroid cup deeply buriedinbrain tissue and with- 
out alens. This cup does not come in contact with either of the 
three lenses shown in.the more anterior sections. 
Finally, a most remarkable case of supernumerary lenses is 
illustrated by figs. 9 and 10 and the outline fig. 11 shows the 
position of these lenses in the entire head (see also plate II, 
fig. 4). Two defective eyes each possessing a lens areshown in sec- 
tion, fig. 10, and a third lens lies between the eyes. In a more anter- 
ior region, fig. 9 and plate IJ, fig. 4, is found another section of this 
third lens, C, and a fourth additional protruding lens lies below it. 
These gases might be enumerated and illustrated until they ran 
into the scores, but sufficient evidence has been given to prove 
that the crystalline lens in these embryos does not depend upon 
a contact stimulus of the optic vesicle for its origin from the ecto- 
derm but originates independently. 
6 Is the Lens-Plate or Lens-Bud Capable of Differentiating into a 
Lens without Contact with the Optic Cup? 
The above question is convincingly answered in the affirmative 
by the evidence given in the foregoing discussion. In the older 
embryos it is clearly shown that supernumerary lenses are as 
highly differentiated and as perfectly formed in all respects as 
are the lenses in the eyes. LEyeless individuals, as figs. 1 and 5 
and plate II, fig. 3, indicate, may possess perfectly formed trans- 
parent lenses which appear in the living specimen as clear refrac- 
tive bodies. 
THE AMERICAN JOURNAL OF ANATOMY, VOL. 10, NO. 3. 
