| 1132 1133) and 1138 (gotopes whose faster decay rates weald tend to \ower the valve it was evidem from the short half life and tagh level of radioactivity ef two samples of Asparagupeis collected em April 3 1954 at Parry I2- lead that these algae were c ncestrating a receatiy formed isotape The velues for the counts of these samples were 12. 600 and |), 600 din/g ee appeced :o an average value of 260 d/m/g based on radioactive decay af eemplee collected in tne same losality on March 6 1954 The tacrease la specific activity might have bees due to material reeuiting from the Mar: 27 teet at Bikiai Atoll, since it was cbeerved that the beck grouad coust ot Parry lslaed iacreesed a few days afier this date Changee in the activity levels ia the signe would be enpecied to fcilow closely these of a envircament, for it hes been showe im ishoretory wets wat 1!3! eptahe reaches equilibrium after the first Beer ia Aecuphyiiam (4) and ater three hours ia .aminerta (7). As laboratory teete ave ant been conducted with Asparagupeis to determine Mis «5. it canmet be stated with certaiaty that it eould behave simflarly it Beas been Lnown for many yooru @it todinege ia preecat ia the sve aad ia a majertiy of the algme (8), in Asparagepeis iedine censtitutes 0. 692 perces of the dry matter (2) Laboratery experiments have indicsted thst certain algne wil! concentrate 1'3! trom sea water (3.4.7) The observations made at Eaiwetot é@uriag the present laveetigations support theee Madiagn stece ihe 1'3) cnecentration in Aspersgopets wes appronimately 18, 000 times thet of the surrcentiag water (The total activity of Aten -6-