AXURIDA. 447 



Fig. 2-3. Horizontal section taken across the vesicles of 



the ventral tube. x 200. 

 Fig. 24. Portion of the ventral groove : region of the 



meta-thorax. x 200. 

 Fig. 25. Organ of unknown function situated on the 



floor of the fourth abdominal segment, x 320. 

 Fig. 26. Three successive transverse sections through the 



ventral groove; (a) in the head region; 



(b) in the prothorax ; (c) in the meta-thorax. 

 x 800. 



Plate III. 

 Fig. 27. Reconstruction of sections taken through the 



head close to the middle plane. x -360. 

 Fig. 28. Section passing through the junction of the 



fore-gut with the mid-gut. x 360. 

 Fig. 29. Transverse section across the oesophagus. 



x 600. 

 Fig. 30. Section of wall of mid-gut. x 1,200. 

 Fig. 31. Transverse section taken across the rectum 



together with the vagina and its median 



diverticulum. x 550. 

 Fig. 32. Transverse section of the ductus ejaculatorius. 



x 550. 

 Fig. 33. Blood corpuscles from a living animal, x 1,200. 

 Fig. 34. Vertical section through the post-antennal 



organ and two of tin: eves (partly after 



Willem). x 1,000. 



Plate IV. 



Fig. 35. Diagrammatic figure of Anurida showing the 

 relations of the principal internal organs to 

 one another. x circa 40. 



Fig. 36. Figure showing the termination of Hie ventral 



