166 ROY L. MOODIE 
§ 8 ee 
¥ i 
Cutie, BY 
\ SANA op \ \ ue oe 
RANI NNNI NN eons 
a: 
cl icky: g, st. h. ie “a we pmx. 
Fig. 2. Sagittal section of the cephalic region of Bothriolepis. >< 1. Drawn 
by Professor Patten. 
cl., cloacal opening hi.h?., bony plates covering the first 
cl.p., oval bony plate over-lapping and second hyoid arches 
the cloacal opening m., mouth 
g., gills md., mandible 
p.mx., premaxillae 
other letters as in figure 1 
Fig. 3 Nodules from the Waverly shales, (Mississippian) of Kentucky, 
containing the brain and ear of Rhadinichthys deani Eastman. X 1. Courtesy 
of Doctor Eastman. 
Fig. 4 The oldest known fossil vertebrate brain; drawn with the aid of a 
reading glass from the photograph (fig.3). Rhadinichthysdeani Eastman, a Mis- 
sissippian ganoid, a member of the family Paleoniscidae, related to the modern 
sturgeons. The posterior part of the brain has been broken away. At the ante- 
rior tip of the olfactory tract is seen an enlargement which may be the olfactory 
sac. Just posterior to the thalamus are two diverging ridges which doubtless 
represent venous blood vessels. > 10. The original photograph (fig. 3) from 
which figure 4 is made shows under a lens all of the detail which is shown in figure 
4, with perfect distinctness, though this detail is not visible in the half tone 
reproduction. 
