EXPI.ANATION OF PIRATE XVIII. 



Fig. 26. Ventral seta of Pristina longiseta. 



,, 27. Dorsal seta of Pristina longiseta, showing thorn-like projections. 



,, 28. Corpuscles of the body-cavity of Pristina longiseta. 



,, 29. Anterior part of a specimen of Pristina longiseta, showing an arrange- 

 ment of the septal glands, with the ducts of those of the third 

 segment. 



,, 30. A septal gland of the sixth segment of a specimen of Pristina 

 longiseta, showing attachments to oesophagus and body-wall. 



,, 31. Anterior part of Pristina longiseta, to show shape and relation of 

 cerebral ganglion. 



,, 32. Anterior part of ventral nerve cord of Pristina longiseta to show 

 " button-holing." 



,, 33- Genital setae from the sixth, segment oi Pristina longiseta ; the distal 

 end is upwards. 



,, 34. Modified ventral seta from the fourth segment of a reproductive 

 individual of the species Pristina longiseta. 



,, 35. Eyes and '' Nebenaugen " of Slavina punjahensis. 



,, 36. Ventral seta of Slavina punjahensis. (The ventral prong of the fork 

 is shown slightly too short.) 



,, 37. Dorsal seta of Slavina punjahensis with small thorn-like projections. 



>y 38, '39, and Plate XIX, fig. 40, stages in the development of the repro- 

 ductive organs of Pristina. Figure 38 is a specimen of P. lon- 

 giseta, and shows also the septal glands with their ducts; fig. 39 

 is probably P. cequiseta, and fig. 40, Plate XIX, is also P. caquiseta. 



