ANATOMY AND DEVELOPMENT OF PEEIPATUS CAPENSIS. 231 



which passes to the jaws, and a little in front of this, apparently 

 from the supra-oesophageal ganglion itself, a second nerve to the 

 jaws also takes its origin (PI. XVIII, fig. 22/ ^^). These two 

 nerves I take to be homologous with a pair of pedal 

 nerves. 



Between the nerves to the jaws and those to the oral 

 papillae a number of small nerves take their origin. Three of 

 these on each side pass in a dorsal direction and one or two in 

 a ventral one. 



The Snpra-oesophageal Ganglia. — The supra-oesophageal gan- 

 glia (figs. 8 and 22) are large, somewhat oval masses, broader 

 in front than behind, completely fused in the middl^, but 

 free at their extremities. Each of them is prolonged 

 anteriorly into an antennary nerve, and is continuous behind 

 with one of the oesophageal commissures. On the ventral 

 surface of each, rather behind the level of the eye, is placed a 

 very peculiar protuberance (fig. 22 d), of which I shall say 

 more in dealing with the histology of the nervous system. 



A number of nerves arise from the supra-oesophageal ganglia, 

 mainly from their dorsal surface. 



In front are the immense antennary nerves extending along 

 the whole length of each antenna, and giving off numerous 

 lateral twigs to the sense organs. Near the origin of the 

 antennary nerves, and rather on the dorsal surface, there spring 

 a few small twigs, which pass to the skin, and are presumably 

 sensory. The largest of them is shown in PI. XVII, fig. 19 a. 

 About one third of the way back the two large optic nerves 

 take their origin, also arising laterally, but rather from the 

 dorsal surface (PI. XVII, fig. 19 d and e). Each of them 

 joins a large ganglionic mass placed immediately behind the 

 retina. Nearly on a level with the optic nerves and slightly 

 nearer the middle dorsal line a pair of small nerves (fig. 19 d) 

 spring from the brain and pass upwards, while nearly in the 

 same line with the optic nerves and a little behind them a 

 larger pair of nerves take their origin. 



Behind all these nerves there arises from the line of suture 

 between the two supra-oesophageal ganglia a large median nerve 



