NOTES ON THE ANATOMY OF DINOPHILUS 61 



which is slightly exaggerated), and vesicula seminalis, being laterally placed, would not 

 appear in a strictly median section. The two ciliated rings of each of the five segments 

 of the hody are indicated by one of the brackets to which the numbers 1, 2, 3, 4, 5 refer. 



FiQ-. 4. — Spermatozoon. 



Fia. 5. — Ventral view of part of the posterior end of a young male, as seen in a com- 

 pressorium. The vesicula seminalis is still very young and nephridium-like, opening at its 

 Internal end into the cavity of the testis. The existence of the structure marked " duct P " 

 was not established with certainty. 



Pig. 6. — Longitudinal section of head, almost median, showing one of the oesophageal 

 nerves. 



Fia. 7. — Horizontal section of eye. 



Fia. 8. — View, seen from the front, of the surface of the head of an individual killed 

 with hot corrosive sublimate. 



Fia. 9. — Transverse section through the head, passing through the origin of one of the 

 oesophageal commissures. 



Fia. 10. — Transverse section through the region of the first postoral pair of ganglia. 



Fia. 11. — Transverse section through the middle region of the body of a young individual 

 (probably a male). 



Fia. 12. — Longitudinal vertical section, not median, passing through the two ovaries of 

 one side of the hody, of a young female. 



Fia. 13. — Transverse section through the middle region of the body of an adult male. 



Fia. 14. — Transverse section through the region of the interval between the anterior 

 and posterior ovaries of an adult female. 



Fia. 15. — Ventral view of an adult male, as seen under strong compression in a com- 

 pressorium. The figure represents the results of a long series of observations. The 

 vesiculae seminales have been drawn at a rather young stage of development ; at their 

 period of maximum development they would appear very much swollen, and would extend 

 forwards as far as the posterior end of the stomach. The double ciliated rings of the five 

 segments are indicated, as in fig. 3, hy the numbers 1, 2, 3, 4, 5. The testis is not shown 

 on the left side of the figure. 



