198 



COMPARA TIVE ANA TOMY 



CHAP. 



dseum, /</) stretches to the most anterior end of the body, to emerge 

 generally separately from the oral aperture in front of and above it. 

 The whole proboscidal apparatus is entirely separate from the intestinal 

 canal. The rhynchoda-um thus leads through the proboscidal aperture 



r 





JJ 



-rd 



Fin. 131. Diagrammatic representation of the proboscidal apparatus of the Nemertina. A, 



Proboscis withdrawn. /;, Proboscis protruded. /, Proboscis ; /v, proboscis slic-atli ; ?-s//, cavity of 

 the latter ; s/, stylet ; <nl. j>oison glanil ; mi, rotractor iiiusflc ; r<l, rliynchodieum. 



into the central cavity of the prol)oscis which closes blindly behind. 

 The wall of the long proboscis is extremely muscular, the arrangement 

 of the fibres being occasionally very complicated. It is internally 

 lined with epithelium which is continued on to the rhynchodamm, 



