7'6 K. KISHINOUYE. 



found .some cpihlast cells (Hg. 68, iii.c.). 'I'lies^e C'[)ib]nst cells seem to 

 take no part in tlie tnnnalion of tlie liiteral eomniissure. Tlicy form 

 probably tlie menibrane covering tlie ner^()lls system. 



Cells of the nervons system, facing the centre of the egg and ly- 

 ino- near the mediajt line of each nervous tlrlckenino', become chaneed 

 into fibres. The fibi-es of the ganglia as well as those of the Ijrain and 

 of the o})tic ganglia of the lateral eyes commnnicate with one another 

 and foi-m the longitudinal commissure (fig. 51). The fibres develop 

 internally and form the lateral commissui-es (figs. 14, 45. 52). There 

 is only one lateral commissure in the bruin : — at the posterior portion 

 of tlie 1)rain proper (fig. 69). The lateral commissure does not de^ elop 

 in the segments of the first and second appendages (fig. 51). The 

 fibrous portion of tlie central cord develops externally and innervates 

 the appendages (figs. 1-1, 62, 69). 



Eyes. 



The lateral eyes make theii* appearance as small epiblastic 

 thickenino's with shalhjw invaginations, just at the margin of the 

 ventral plate, and at al)out the level of the posteri(jr end of the external 

 cephalic groove (fig^. 1^, 35, 59, 60). At this stage they are not 

 distinctly seen in the preser^ed eggs nor in tlie surface- view }>rej)an!- 

 tions. Thev are distinctly seen in sectioiis only. Ihis is due to their 

 verv small size and also to their being placed near the cephalic thicken- 

 ing of the nervous svstem and neai' the anterior end of the thick 

 mai'uinai band, liut in one or t\vo days alter their formation when 

 thev arc a little rem<ned exteriorly and posteriorly from the cephalic 

 thickening (fig. 13), and then from the marginal band (fig. 14), they 

 become easily recognisalde in the sin*face-view ]>reparations. As they 

 are thus removed, ilie o]»ening of their invaginations is directed 

 ])osieri<>fl\ and dorsalh. Ilie lliickeiiiiig i> nioi-e (haii one-cell tlii(;k. 



