Opt.hs 



opt.n.^ ^ 



tr.com. 



Fig. 2IO. A plan of the nervous system of Chirocephahis. ob.z, second ab- 

 dominal somite ; an.' antennulary nerve ; ati/' antennary nerve ; an."co?n. com- 

 missure for fibres which unite antennary ganglia ; brti. brain ; fr. nerve to 

 frontal organ; ga. ganglion of ventral cord; tn.e. nerves to median eye; md. 

 mandibular nerve; 7nx.' maxillulary nerve; 7nx." maxillary nerve; oe. oeso- 

 phagus; oe.com. circumoesophageal commissure; opt.l. optic lobes; opt.n. 

 optic nerve; th.\, first thoracic somite; th.iz, nerve of last thoracic somite; 

 tr.com. transverse commissure of ventral cords. 



