106 PROCEEDINGS OF THE AMERICAN ACADEMY 



Plate I. 



Fig. 1 Aulophorus vagus, dorsal view. The actual length is indicated by 

 the straight line at one side of the figure. 



Fig. 2. Poilal stylets, such as form the first four pairs of ventral fascicles. 



Fig. 3. Podal stylets, such as occur in the ventral fascicles after the fourth 

 pair. 



Fig. 4. Fascicle of dorsal stylets. and bristles. 



Fig. 5. Diagram of the circulation in tiie pavilion, dorsal view. 



Fig. G, Diagram of circulation in the head, dorsal view. 



Fig. 7. Blood-vessel : a, expanded ; fi, contracted. 



Fig. 8. Segmental organ. 



Fig. 9. Frontal section tiirough the ventral part of the anterior end of body, 

 showing the commissures and part of the ventral nervous cord. 



Fig. 10. Frontal section through the ventral nervous cord. 



Plate II. 



Fig. 11. Sagittal section through the head and pharynx, mu., muscle fibres 

 used to protract the pharynx. 



Fig. 12. Cells of tlie walls of the upper space of the pharynx. 



Fig. 13. Dermal glands in the living animal. 



Figs. 14, 15. Outlines of cross sections of the pharynx. 



Fig. 10. Cross section of the pharynx. 



Fig. 17. Cross section of the oesophagus at the 9th ring. 



Fig. 18. Dermal cells. 



Fig. 10. Frontal section through a lateral half of the brain. 



Fig. 20. Cross section through a lateral half of the brain, cl'., connective 

 tissue forming the neurilemma. 



Plate III. 



Fig. 21. Isolated nerve cells from the brain. 



Fig. 22. Cross section through the region of the bristle sacs. 



Fig. 23. Cross section near a partition. 



Fig. 24. Cross section near the region of the bristle sacs. 



Fig. 25. Sagittal section through the brain and one commissure. 



Fig. 20. Sagittal section through a lateral half of the brain. 



Fig. 27. Frontal section through the brain. 



Fig. 28. Cross section of the intestine. 



Fig. 20. Section cut obliquely through the region of the pavilion. 



Fig. 30. Cross section of one of the digitiibrm appendages. ?«u'., branched 

 muscle cells. 



Fig. 31. Sagittal section through the region of the pavilion, cut somewhat 

 obliquely. 



