80 



FACTORS AFFECTING CILIARY ACTIVITY 



both mechanical activity and the rate of beat are known to increase 

 with increase in temperature. This does not necessarily mean, 

 however, that cilia will beat faster in summer than in winter, for 

 many factors combine to control the rate of ciliary activity; 

 indeed, Usuki and Koizumi (1954) found that the ciliary activity 



10 



15" 20° 25" 



TEMPERATURE 



JO' 



35" 



Fig. 18. The effect of temperature on the rate of movement 

 of small particles by the frontal cilia of Mytilus. Observations 

 shown here were made as soon as the tissue reached the required 

 temperature. Activity fell away with time at temperatures of 

 30°C and above (from Gray, 1923). 



of the gills of Ostrea gigas was at a maximum in winter and a 

 minimum in summer, and they were able to correlate these 

 changes with variations in the state of maturation of the gonads. 



The effect of temperature on the rate of movement of small 

 particles by the frontal cilia of the gills of Mytilus was studied by 

 Gray (1923), and his results are showTi in Fig. 18. There is a 



