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ANN BISHOP 



the mouth. They were evacuated in the same manner as were 

 the remains of the nutritious particles. Smaller clumps of 

 carmine move more rapidly than larger clumps. 



In cases where the animals were full of balls of nutritious 

 material before feeding, it could be seen that the carmine balls 

 moved backwards more rapidly than did nutritious balls. 



A similar experiment in which Indian ink was used instead 

 of carmine gave identical results. 



Text-figs. 3 and 4. 



The above observations differ from those of Lund (16) on 

 Bursaria, in that in Spirostomum the ingested material follows 

 a definite course through the body. When the material ingested 

 is of a nutritious nature, the balls travel to the anterior end 

 and then move backwards following a course parallel to the 

 meganucleus. In her work upon the food vacuoles of Car- 

 chesium, Greenwood (8) states that the food vacuoles travel 

 round the meganucleus. In Spirostomum ambiguum, 

 and in Paramoecium also, according to Metalnikov (20), 

 substances of no nutritive value take a much shorter course, 



