220 
IOWA ACADEMY OF SCIENCE 
Harrison, R. G., ’01, Ueber die Histogenese des peripheren Nervensystems bei Salmo 
salar. Arch. f. mkr. Anat. Bd. 57, p. 354. 
, ’06, Further experiments on the Development of Peripheral Nerves. Amer. 
Journ. Anat. Vol. 5, No. 2, p. 121. 
SCHAPER, A., ’97, Die fruhesten Differenenzierungsvorgange im Centralnervensystem. 
Arch. f. Entwick. — Mech., Bd. 5, Heft 1, p. 81. — Abstract in Science, N. S., Vol. 5, 
No. 115, p. 430. 
EXPLANATION OP FIGURES. 
Fib. I. Transverse section of neural tube and spinal ganglion of a 12 mm. embryo of 
the pig. XI65. ' 
dnr — dorsal nerve root, spg — spinal ganglion, nb — neuroblast, vnr — ventral 
nerve-root, ic — indifferent cells. 
Fig. II. Transverse section of neural tube and spinal ganglion of a 6 mm. embryo of 
the pig. XI65. 
ic — indifferent cells. dnr — dorsal nerve-root. nb — neuroblast. spg — spinal 
ganglion. 
