388 THE BIOLOGY OF HYDRA : 1961 



TABLE 1 



Food catching ability vs. Age 

 Series I (about 2.0 Artemia/hydranth — fresh sea water) 



TABLE 2 

 Ingestion time vs. Hydranth age 



Age of hydranths 12 3 4 



No. of hydranths tested 31 26 52 18 16 



Average time for ingestion in seconds 257 256 300 295 237 



Campamilaria? How do they differ from young ones? Dr. Crowell 

 (who did much of the basic work upon which this study is based) 

 and I have measured a number of physiological capacities vs. age 



Fig. 14. Photomicrograph of Cam- 

 panular'ia ingesting Artemia labeled 

 with fluorescent dyes (0.1 % acrifla- 

 vine). From a time lapse sequence. Note 

 appearance of fluorescent digest in 

 upright proximal to upper hydranth. 



