SEA-FISHERIES LABORATORY. 441 



superior and inferior legumentary neuropiles situated in 

 the posterior region of the brain, slightly anterior to the 

 neuropiles of the second antenna. 



At each side of the brain there is a globular mass of 

 radiating fibres lying between the oculomotor and the 

 tegumentary nerves. This is the globulus. There is a 

 tract of nerve fibres extending from the globulus to the 

 median optic neuropile. It is probable that some of the 

 fibres of the otocyst nerve arise from the globulus. 



The chief groups of nerve cells in the brain are as 

 follows : — 



The supero-median cells are on the inner side of the 

 antero-dorsal region of the brain. 



The infero-median cells are situated on the ventral 

 side of the posterior part of the brain near the median 

 line. 



The supero -lateral cells are situated dorsally on the 

 inner and anterior side of the globulus. 



The infero -lateral cells extend along the inner side of 

 the globulus on the ventral side of the brain. 



The anterior globular cells are situated ventrally on 

 the inner and anterior side of the globulus. 



The posterior globidar cells lie above and behind the 

 globulus at its outer and posterior side. 



The following nerves are connected with the brain 

 (fig. 68):- 



Optic nerve (o. n.). One pair. Each arises from the 

 dorsal side of the brain at its anterior corner. The fibres 

 are continuous with those of the various optic neuropiles. 

 It runs outward and forward at an angle of 45° with the 

 longitudinal axis, and passes into the distal part of the 

 optic peduncle, where the latter articulates with the 

 proximal part of the peduncle. In the swollen part of 

 the peduncle the nerve becomes enlarged to form the optic 



