REFERENCE LETTERS.
Reading edition
a = flagellum in Fig. 27, that is supposed to extend centrad beyond the nucleus.
b = twin flagella in Fig. 27, of which the centrad continuation is seen applied against the distal surface of the cells and to be continued centrad.
c = capsule of lens.
cf = axial fibers of cells extending centrad.
co = cornea.
concr = concretion cavity.
ec = ectoderm.
en = endoderm.
f = flagella.
flp = distal fiber of a long pigment cell.
fpr = axial nerve fiber of a prism cell.
fpyr = axial nerve fiber of a pyramid cell.
frc = axial nerve fiber of the retinal cells of the simple eyes.
gc = ganglion cells.
ind = impression of the lens probably due to the pressure of weight against the surrounding tissue.
l = lens.
lp = long pigment cells.
m = muscle fibers.
namp = nuclei of ampulla cells.
nc = network cells (Figs. 13 and 16), and nettle cells (Figs. 28, 29).
nf = nerve fibers and tissue.
nlp = nucleus of long pigment cell.
nm = nucleus of muscle cells.
nprc = nucleus of prism cell.
npyrc = nucleus of pyramid cell.
nz = nuclear zone.
pr = prism of prism cell.
prc = prism cell.
pyr = pyramid of pyramid cell.
pyrc = pyramid cell.
pz = pigmented zone.
r = retina.
s = secretion in endo. of tent. and ampulla.
sh = shrinkage space.
sec = vitreous secretion in the lumen of the simple eyes.
sla = supporting lamella.
vb = vitreous body or zone.
x = (1) the approximate level at which Fig. 4 should be cut transversely to give Figs. 1 and 3. (2) the thickening of the supporting lamella in Fig. 13 to support the lens.
* = Point of approximation of cells of lenses in Figs. 7 and 13.