62 



Our Food Mollusks 



larger quantities of carmine grains are used, their num- 

 ber finally causes the palps to reject them, the ciliatet. 

 margins often being folded over so as to sweep clean 

 even the striated surfaces of the palps, if carmine has 

 fallen directly on them, and they are able to clean them- 

 selves in still another way that cannot be described here. 



Fig. 15. — Cilia currents on mantle («i) and palp (/>) of the 

 oyster (Ostrea virginica). 



The general direction of currents and the possible 

 routes for food or mud in the mantle chamber of the 

 oyster will be understood without description by a study 

 of Figures 3 and 15. The gills are represented as hav- 

 ing been removed in the latter figure, their former line 

 of attachment to the mantle being shown by the line C. 

 It will be seen that undesirable matter is cast out of the 

 body over the edges of the mantle between the points A 

 and B, and that this is the most favorable region for such 

 a discharge. If farther back, as below C, this would 



