GIGANTOCYPRIS MULLERI 



231 



They soon give off branches to 

 the labral glands (Fig. 14). From 

 the labral ganglion a small nerve 

 runs downwards towards the tip 

 of the labrum (Figs. 11, 12). It 

 supplies various dilator muscles of 

 the mouth region and then ends 

 in a small distal labral ganglion. 

 Dorsally the labral ganglion sends 

 off two nerves. Of these the anterior 

 runs up to the ganglion which in 

 Doloria I have termed the stomach 

 ganglion. I call it the labral connec- 

 tive. In Doloria this nerve passes 

 through the frontal foramen of the 

 brain (Cannon, 193 1, p. 471). In 

 Gigantocypris there is no such fora- 

 men, but in the homologous position 

 the nerve sends forwards a small 

 twisted median nerve, the aortic 

 connective, which joins directly the 

 hinder wall of the brain (Fig. 12). 

 It is possible that this connective 

 is also present in Doloria but that I 

 could not find it on account of its 

 size. 



From Fig. 1 2 it will be seen that 

 the upper part of the labral con- 

 nective runs close underneath what 

 may be termed the floor of the 

 aorta, that is, the lower median 

 wall where the aorta bifurcates 

 immediately behind the brain. Just 

 at the junction where the aortic 

 connective emerges from the labral 

 connective a nerve is given off 

 which immediately penetrates the 

 aortic floor and branches into a 

 plexus which spreads over the latter. 

 The terminations of this plexus can 

 be seen with certainty ending against 

 the flattened nuclei in the neigh- 

 bouring aortic walls. 



The labral connective shows a 

 series of at least three swellings. 

 Between the upper two a branch 



Fig. 16. Oblique view of nervous system and ganglia of nauplius eye, 

 based on an isometric projection, to show the extent and arrangement 

 of visceral nervous system. All nerves behind the antennal have been 

 omitted, ao.g. aortic ganglion; /./. labral loop of visceral system; 

 l.n.e. ganglion of lateral component of nauplius eye; tn.ao. aortic 

 muscle; m.ao.oe. aortic-oesophageal muscle; m.pc.d. pericardial 

 dilator; m.n.e. ganglion of median component of nauplius eye;«.a.i, 

 antennulary nerve ; n.a.2, antennal nerve ; n.fr. nerve to frontal organ ; 

 n.p.e. nerve to paired eye ; st.g. stomach ganglion ; v.n. visceral nerve 

 as it emerges from nerve ring. 



