NERVOUS SYSTEM OF PYCXOGOXIDS 469 



than the others mentioned. The first larval stage soon attaches 

 itself to, and enters hydroids. It has three appendages in the 

 first larval stage, one pair is chelate, the last two have long ten- 

 dril-like extensions. At such a period the nervous system is 

 not easily made out from surface views, but it is much like that 

 of Ammothella. Figure 8 shows three parts, a larger thicker 

 portion which has nerves to the larger first appendages, and 

 on each side back of this a group of cells corresponding to the 

 other appendages. A moult within the hydroid gives rise to 

 a small larval form without the long appendages and it is at 



16 



Fig. 14 Outline of ventral view of larva and ganglia from below A. crectus, 

 third larval stage. X So. 



Fig. 15 Outline of a ventral view of a later stage larva than figure 14 of A. 

 erectus. X 85. 



Fig. IG Outline of a dorsal view of a larva of A. erectus about the same stage 

 as figure 14. The brain is shown. X S5. 



Fig. 17 Fourth stage larva of A. erectus from below. X 35. 



Fig. IS Central ganglia of a larva of A. erectus with three pairs of walking 

 legs. The drawing is from below. The upper area without nerves in the figure 

 is the supraesophageal ganglion. X 35. 



