EXPLANATION OF PLATE XIX. 



Ptychodera hedUyi, sp. nov. 

 Fig. 1. Transverse section through the anterior region of the central 



proboscis organs, x 65. 

 2. Transverse section at the level of the " notochordal " blind 



sac. x 65. 

 3. Transverse section passing through the " end plate " of the 



proboscis skeleton, x 65. 



4. Transverse section of proboscis neck just in front of the posterior 

 end of the ventral proboscis pocket (vp.). x 65. 



5. Transverse section passing through the proboscis pores (p.) x 65. 



6. Nearly median sagittal section through the proboscis neck and 

 anterior portion of collar, x 50. 



[For Reference Letters see pages 345-6.] 



