TUBIFEX. 401 



Fig. 41. A figure drawn from a living specimen to show 

 tlie arrangement of the blood vessels in the 

 prostomium and first five segments of the 

 body. The coiling of the perivisceral vessels 

 is slightly simplified. x about 220. 



Fig. 42. A figure drawn from a living specimen to show 

 the arrangement of the blood vessels in an 

 intestinal segment. x 180. 



Fig. 43. A diagrammatic representation of a complete 

 nephridium. 



Fig. 44. A small portion of the nephridial tube covered 

 with vesicular, peritoneal cells — drawn in the 

 living condition. 



Plate VII. 



Fig. 45. Longitudinal section through the spermiducal 

 gland, prostate and penis. x 110. 



Fig. 46. Transverse section of the nerve cord. x 630. 



Fig. 47. Longitudinal section of a nephrostome with the 

 preseptal part of the nephridial tube, part of 

 the body wall and septum. x 520. 



Fig. 48. Longitudinal section of an ampulla of a 

 nephridium. x 790. 



Fig. 49. Spermathecae Liberated from the body through 

 a rupture in the body wall caused by pressure. 



x 50. 



Fig. 50. Externa] form of a very Large spermatophore. 

 x 55. 



