A FISH BRAIN FROM THE COAL MEASURES . 165 
Fig. 1 Outline of the cephalic region of Bothriolepis. Seen from the neural 
surface, showing the probable size and location of the brain and principal sense 
organs. The occular plates are not shown. X 1. Drawn by Professor Patten. 
au., membranous labyrinth ol.o., olfactory organs 
d.e., ductus endolymphaticus p.e., unpaired parietal eye 
e., vertical ethmoidal plate p.e’., paired parietal organs 
l.e., lateral eyes b.pl., membranous or cartilage plate 
0.0l., opening to olfactory organs forming the floor of the endocranitum 
