Effect of Aleohol and Anesthetics on Development. 373 
defect which was common in the Meg experiments. Individuals 
may have one normal eye and the other eye in different conditions 
of arrested, development from slightly small and defective to 
entirely absent, see figs. | and 2. An important point that was 
brought out by the alcohol monsters which was not noticed in 
the magnesium specimens is the fact. that some of the embryos 
have both eyes equally small and defective, figs. 3, 8, 9, 10, and 11. 
The two eyes are symmetrically defective and the head appears 
to have small eye-spots instead of normal eyes; compare figs. 3, 
and 7, 9,10 and 11 and 12. Finally, as in Mg solutions so also 
in the aleohol, many eyeless individuals are present . 
The eye in some of the alcohol monsters is rather different from 
that found in the Mg embryos, and may possibly serve to indicate 
something of the condition of the eye anlagen in the brain. Many 
embryos possess optic cups with their concave surfaces facing 
almost directly toward the median sagittal plane of the head. In 
life the eye presents a heavily pigmented solid convex surface to 
the side of the head instead of the usual open pupil through which 
the lens may be seen within the cavity of the optic cup. Fig. 
5 and 6 show front and lateral views of such an embryo; the side 
view indicates the peculiarly solid convex object seen when looking 
towards the lateral eye. Fig. 18 represents a section through 
this eye. The choroid coat of the eye-ball is pressed close against 
the body wall on the sides of the head and the concave retinal 
surfaces which should face outward are turned directly towards 
one another; a lens lies between the two eye components which are 
really separate except along their dorsal borders. Fig. 4 shows 
a somewhat similar specimen in which the eyes are entirely sepa- 
rate yet they have an arrangement almost identical to that 
just deseribed. The eyes face the mid-plane of the head and 
turn their convex choroid coats out against the body wall. The 
only place at which the inner face of the eyes touches the ecto- 
derm is the ventral body wall and from this a lens has arisen and 
lies between the two eyes. Fig. 14 illustrates a section through 
these eyes, in which a most peculiar arrangement exists. Optic 
fibers probably arising from the ganglionic layer of the retina, 
(although this can not be positively demonstrated in the sections), 
