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bones apparently. The adjacent eyeballs seem to be distinctly separate, 
a pair of eyelids for each, though upon careful examination they seem 
to occupy a common orbital fossa. The frontal region of each is 
distinct, though they seem to fuse at the line between the two heads. 
Beaks, palates and tongues look normal. The beaks make an angle 
of about 40° with each other. Upon dissection the two frontal bones 
are separated by a distinct suture. Mach frontal bone shows a median: 
suture so that four centers of ossification exist. Upon removal of the 
tissues over the orbit a single orbital fossa is exposed occupied by 
a single eight-shaped eyeball (Fig. 7). Upon each segment of the eight 
% 
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Fig. 6. Rio. 7. 
Fig. 6. Chick showing partial duplication of the head. 
Fig. 7. Dissection showing co-shaped (fused) middle eyeball. 
is a cornea. Upon carefully lifting the collapsed eyeball from the 
orbital fossa, two optic foramina and two optic nerves are seen. Appar- 
ently there were originally two distinct eyeballs that were gradually 
crowded together until partial fusion occurred and so prevented an 
orbital septum forming. The fusion, however, is not extensive as ex- 
hibited by the presence of the two optic nerves. 
7. This chick monster was still in the shell and has been left 
in that position. This specimen shows failure of development of the 
upper part of the beak. The upper division ended in a mass resembling 
the trochlear end of the humerus. This mass rested upon the tongue 
