82 MINUTE STRUCTURE OF THE BRAIN AND CORD OF ARACHNIDS. 



Fig. 6s. — Brain of young Limulus about three inches long, seen from the neural surface. The cerebral hemi- 

 sphere, on the left, is shown in optical section, at the level of the giant association neurones, H. as, and on the right, 

 at a deeper level, showing the principal cerebral lobes and the gustatory tracts, G. ctr^. and g. tr.^ Compare with 

 Fig. 48. On the right, behind the hemispheres, the superficial arrangement of the clusters of nerve cells, and 

 the cranial nerves are shown. On the left are seen the gustatory nerve roots, the great longitudinal gustatory 

 tracts, the principal neurones and their relation to the neural commissures, and the principal neuropile masses 

 in the pedal and stomodeeal ganglia; methylene- blue preparation. 



