(55) 



by tt:e violent extraction of the ho oa v.r.en emersea in the fix- 

 iru^ -fluia. Tiii b unaov!btediy is the saire condition that Master- 

 TTian (15) nas described and the s azrie structure that ne i;ag hor;iol- 

 ogized to the "neuropore" of the Chordata or that he has com- 

 pared to the tubular aoraal nervous system of the same type as 

 that of Balaiioglossus. (Q J vol. xl , P. 295,296) It shoula 

 be mentionea, h.o'.vevor, tiiat Kasteraan (16 b) in do answer to 

 Roule hs.s adJTiittea the error of ..is rather hasty conclusion. 



Menon (17) has recently described a tubular nerve ganglion 

 for a eerv-i.in Actino trocia. but I must believe ti:at the struc- 

 ture is uue to fixation. 



Immediately posterior to the ganrlion a cross section 

 shov.'s two thickenings of the subepideriral nervous system. These 

 •hicKenings are what Masterman has describea as the dorsal long- 

 itudinal nerves and they can be traced from the ganr^lion. They 

 are almost exactly betv/een the dorsal muscle tract and the epi- 

 aer-is o^' tj:e aorsal wall, A little farther back these so-callc; 

 nerves are net quite as distinct but wh.en tne region of the 

 'Irst pair of' tentacles is reached they become more prominent 

 again and diverge, passing do;rn the lateral walls along the ba- 

 ses of the tentacles. (7ig.4l) They meet in the ventral region 

 said thus form arin^-like thickenin;^ of tne subepiaermal nervous 

 system which is ujidoubtealy the same tiat ATasterman has de- 



