NBMERTEA ENOPLA 647 



nervous system was found embedded in the longitudinal 

 musculature, as seems still to be the case in some species 

 (Brinkmann, 4), and that its place changed in the different 

 genera, then we understand that we cannot look for primary 

 conditions in this part of the proboscidian system. That the 

 longitudinal musculature of proboscis and sheath are in 

 contact with each other at the place of insertion is quite natural 

 (Text-fig. 19), while they both are part of originally one layer 

 and from one place take their origin. 



TEXT-ric4. 19. 



prob. r-kynch. 



I muse, sept 



S'^ ^1 / lLiti 



o c in. 



d ri.comm 



cu. ni 



6tn 



rhynck 



end. 



cm. 



Dorsal part of a longitudinal section through the anterior region 

 of Balaenanemertes musculocaudatus (Brinkmann) 

 with protruded proboscis (4, PI. 15, fig. 10). 



Brinkmann *s statement that the brains of Pendo- 

 nemertes and Balaenanemertes are situated in the middle of 

 the musculature of the proboscidian system is of the greatest 

 importance ; for we know from Drepanophorus that the 

 longitudinal musculature is in contact with the same parts 

 of the body-wall by a muscular septum, which separates the 

 precerebral or head-region from the brain and the body and 

 always expands just before the ganglia. In the Pelagica this 

 septum as a rule is broken up into several muscles which 

 Brinkmann calls ' Eiisselfixatoren ' and that as a rule lie 

 outside and before the nerve-ring. The brain lies at the same 



