pa.cl.prg. 
Fig. 1 Showing the distribution of the retinal pigment of the common horned 
pout, Ameiurus nebulosus, in darkness (X 160). The rod and cone cells are 
entirely free from pigment and are, therefore, easily demonstrable. 
Fig. 2 Showing the distribution assumed by the retinal pigment of Ameiurus 
in the light (xX 160). The expanded pigment accumulates near the external 
limiting membrane, thereby masking the visual cells. 
ABBREVIATIONS 
ell.bac., rod ellipsoid 
prs.dst.bac., outer member of rod 
ell.con., cone ellipsoid 
prs.dst.con., outer member of cone 
mb.lim.ex.,external limiting membrane _ scl., sclera 
my.bac., rod myoid 
my.con., cone myoid 
pd.cl.pig., base of pigment cell 
st.nl.ex., outer nuclear layer 
st.pig., pigment layer 
553 
