within this species. Further study with such low levels of radioactivity would require a different system then the one used here fn order to overcome the quenching problem which is due to having to use large samples of tissue in the scintillation vials. Special acknowledgement for assistance is due to Gene Helfman who provided the samples and to Larry Roth, Lance Hodges, and Lanny Fisk who helped in the preparation and analysis of the samples. Ariel A. Roth Loma Linda University .