INTERNAL ANATOMY. 6 1 



to be desired. The accompanying figures, taken from 

 Boveri's finely illustrated memoir, show the appearance 

 and topographical relations of the excretory tubules. 



A tubule as seen in the living condition is shown in 

 Fig. 30. It is a curved tube consisting mainly of two 



Fig. 30. — An excretory tubule of the left side, with the neighbouring portion 

 of the pharyngeal wail, as seen in the living condition. The round bodies in the 

 wall of the tubule represent carmine granules. Highly magnified. (After ROVEKI.) 



limbs, bent approximately at right angles to one another, 

 and lying over against the dorso-lateral wall of the phar- 

 ynx. (Cf. Fig. 29.) The anterior limb is directed verti- 

 cally, and the posterior longitudinally. The former opens 

 by a relatively wide and forwardly directed opening into 



