1888.] 



Madreporite of Cribrella ocellata. 



331 



Ludwig* states that he was unable to find any such connexion (a 

 connexion which would explain the injection results obtained by 

 many observers) in the forms investigated by him, and 1 can confirm 

 his statement for Asterias rubens. Neither in A. rubsns nor in 

 Cribrella ocellata have I detected any connexion between the 

 water vascular and " blood vascular " systems in this region of the 

 body. 



Section 1 (fig. 5) passes along the upper extremity of the stone 

 canal between the dilatations, and through one of the abnormal pore 

 canals (PM 2 ) ; by examination of neighbouring sections it is seen that 

 the lumen of the pore canal is continuous from the exterior to the 

 " schlauchfdrmiger Kanai " (Schl) and also that there is a communica- 

 tion between the canals (PM 1 ) and (PM 2 ). Tw.o other canals (PM) 

 are seen opening into the stone canal (St). 



Section 2 (fig. 6) passes through the aperture of communication 

 between the ampulla and the " schlauchfdrmiger Kanal." In this 

 section the continuity of the " heart " or dorsal organ (Ht) and anal 

 " blood " ring (AK) is seen; also a gut vessel (Grt) from the latter. 



Fia. 5. 



* H. Ludwig, « Zeitsckr. Wiss. Zool.,' vol. 30, 1878, pp. 103, 104. 



