NEMERTINEA 



51 



pheral nerve tissue. This network suggests the "most ancient 

 arrangement of the nervous tissue." In the more highly specialized 

 forms, the brain and lateral nerves are more concentrated. Prob- 

 ably all nemertineans have more or less peripheral nerve networks 

 even though Hubrecht might not have seen them by his methods, 

 but the fact remains that those forms in which the network is 

 especially marked are more primitive because of it. Montgomery 

 believes that Haller is mistaken as to the multipolar condition of 

 these cells. 



Fig. 14. Reconstruction of the nervous system of Carinella shown from the 

 ventral side. Figure at the left, side view of a reconstruction of the 

 upper portion of the central nervous system of Carinella. The figures 

 at the right are from cross section taken at various levels. The upper 

 and the two lower figures are from one side only. X75, Hilton. 



In general the central nervous system of the Nemertinea is as 

 follows : A brain composed of two ganglionic masses at the anterior 

 end of the body, on on each side of the proboscis. These are united 



