Langdon, Sense-organs of Nereis virens. 



29 



what I have incidentally observed in some richly stained methylene blue prepar- 

 ations, I judge that Retzius' " vordere Haufen " are merely the palp ganglia 

 mentioned above — ganglia connected only, so far as I can determine, with the 

 retractile tips of the palps. There is no doubt that they are included within 

 the limits of the brain. 



The diffuse sense-organs of the tentacles send their central 

 processes into the axial nerve of these appendages and each of 

 these nerves passes to the anterior border of the brain farther 

 dorsad and nearer the median line than does the axial nerve 

 from the corresponding palp. On entering the brain, each passes 



Text-figure j. A diagram of the left half of the prostomium showing the 

 course of the nerves from the tactile appendages and the special sense-organs 

 into the brain. 



br., outline of brain; e.g., large ganglion cells which lie beside the an- 

 terior eyes and in the adjoining region of the brain; e. a., anterior eye; e. f,, 

 posterior eye ; g., mass of small ganglion cells to which the palp nerve goes ; 

 «., nerve from the supposed sensory area on the base of the palp; n. e. a., 

 nerve from the anterior eye; n. e. p., nerve from the posterior eye ; n.o.c.a., 

 nerve from the anterior paired cephalic organ ; n. 0. c. p., nerve from the pos- 

 terior paired cephalic organ ; n.pal., nerve from the palp ; n. ten., nerve from 

 the tentacle; o. c. a., anterior paired cephalic organ; 0. c, p., posterior 

 paired cephalic organ ; pal,^ P^'p > ten,, tentacle. 



