Central nervous system of Tunica nigra. 197 
éd 
times as dense masses, sometimes as flakes or dots. Vacuoles, 
often containing yellowish pigment, are frequently seen in the 
nerve cells. 
9. Log (1892) and Maenus (1902) have performed experiments 
to determine the functions of the ganglion in tunicates. MaGxus 
concludes that when purely local reactions are obtained from a small 
group of muscle fibers, the nervous system is not involved at all. 
The ganglion is the reflex center for the rather simple but general 
movements of the body. The simple structure with the relatively 
small number of association cells shows a very simple type of central 
nervous system. 
