GIGANTOCYPRIS MULLERI 225 



plane as in the photograph (Plate XLI, fig. 2), but always inside the neurilemma sheath 

 it joins one or other of the laterally placed nerves supplying the lateral components 

 of the nauplius eye (Fig. 13). The latter nerves form the two outside members of the 

 row of four. They are very massive and soon swell up into the large lateral ganglia of 

 the nauplius eye. In between them a pair of small nerves arise which extend forwards 

 along the median lower edge of the nauplius eye. They soon unite and run to the small 

 frontal organ (Fig. 12). Liiders did not discover the small median nerve to the nauplius 

 eye, and as a result mistakenly described the latter paired frontal organ nerve as a 

 nauplius eye nerve. 



At the sides of the brain, just in front of the anterior limit of the nervous mass inside 

 the neurilemma, the nerves to the paired eyes make their exit. These were figured by 

 Liiders as long nerves extending to the bladderlike structures which project from the body 

 wall and represent the vestigial paired eyes (Plate XXXIX, fig. 2). Actually, however, 

 I think the nerves are quite short and it is the paired eye itself which has become stretched 

 and extends into the body as a narrow conical structure which then joins the nerve just 

 outside the nerve ring (Plate XL, fig. 1). The peculiar pattern which is to be seen in 

 the eye itself extends down the narrowing cone well into the body. In addition to this 

 there is a sharp staining difference which supports this view. The nerve, as it leaves 

 the ring, stains orange in Mallory, but at the small swelling (Fig. 13) which I take to 

 represent the junction between the nerve and the eye, the staining reaction changes 



to blue. 



Behind the paired eye nerve is a small nerve which represents the first of the shell 

 nerves. It extends round the sides of the nauplius eye into the valves and spreads out 

 over the most anterior part of the valves. I call it the shell nerve I. Soon after leaving 

 the central nerve ring it is joined to a plexus of nerves running through the antenna. 

 It is figured but not mentioned by Liiders. 



The antennulary nerves arise from the ventral side of the nerve ring as in the case 

 oiDoloria. They enter the antennule almost directly and swell into the large antennulary 



basal ganglia. 



The antennal nerve divides into three as it leaves the nerve ring. The middle portion 

 is by far the largest and represents the large nerve that I described in Doloria as con- 

 taining the giant fibres which enervated the powerful muscles in the base of the antenna. 

 It can be traced in Gigantocypris to a very complicated and double basal ganglion but, 

 as I shall repeat later, it contains no giant fibres. The other two branches of the antennal 

 nerve enervate sundry small muscles in the base of the limb. The anterior nerve receives 

 the connexion with the shell nerve I, which I have mentioned above, but a more 

 important connexion is with the posterior antennary nerve. These two branches are 

 connected together through a plexus of nerves ending on the wall of the end sac of the 



antennary gland (Fig. 13). 



A short distance behind the antennal nerve is an isolated nerve (Fig. 11) figured by 

 Liiders who states (1909, p. 37) that its distribution could not be accurately followed. 

 It is the second nerve supplying part of the valves. It extends laterally close underneath 



