(117) 

 lateral nerve, the gauglion and the nerves to tlie lophophoral 

 organs are new formations. 



All of the nervous struct ureXof the collar and trunk are 

 lost during sietamorphosis except the collar trunk nerve ring, 

 which persists as the nerve ring of the adult. 



The ventral mesentery becomes the oesophageal and rectal 

 mesenteries of the adult aiid the cavities of the trunk and ven- 

 tral pouch are transfoniied into the iafraseptal cavity. 



At least the greater part of the nephridia is lost during 

 me t aiiio rpho s i s , 



The lophophoral organs arise late in the adult life and 

 are present oixly in iiidividuals v/hich are v/ith testes and with- 

 out ovaries. They probably serve as seminal receptacles. 



The vascul9.r system of the adult consists 0"^* an efferent 

 sxjd afferent vessel which are continuous posteriorly by means of 

 a sinus around the loop of the alimentary canal; q-^ caecal ves- 

 sels as outgrowths from the afferent vessel and the blooa sinus; 

 of a distributing and recipient ring vessel, the former opening 

 into the ef-^erent vessel and th.e latter, into the afferent ves- 

 sel; and of tentacular vessels, eacl: of which divides into two 

 short branches, one opening into the distributing vessel and 

 the other, into the recipient vessel. 



There is a ciliated ridge extending alon^ part of the inner 



