OSMOTIC CONSTITUENTS OF THE COELACANTH LATIMERIA CHALUMNAE SMITH

¹ Zoology Department, University of Glasgow, Scotland, U. K.

1. Samples of blood, bile, muscle and liver from a frozen specimen of the coelacanth Latimeria chalumnae were analyzed for ions and nonprotein nitrogenous compounds.

2. Mean values (mM/l) for blood serum (hemolyzed) and bile (figures in brackets) were Na 104.5 (73.8) K 52.8 (58.2), Ca 1.68 (1.75), Mg 4.49 (4.0), Cl 100.1 (77.5), urea 290 (289), trimethylamine oxide 109.4 (107.0), total NPN 786 mg-atoms (1224), osmolality 957 milliosmoles (1135).

3. Mean values (mM/kg water) for muscle and liver (figures in brackets) include Na 30.6 (98.5), K 73.5 (50.1), Ca 1.8 (1.9), Mg 14.3 (9.5), Cl 35.3 (115.5), urea 422, trimethylamine oxide 290, total NPN 1423.

4. A study of the effect of prolonged freezing on the electrolyte distribution of the perch Perca fluviatillis was made and compared with the above results.

5. Latimeria differs from a marine teleost and resembles an elasmobranch in having large quantities of urea and trimethylamine oxide in both blood and muscle, and a high osmotic concentration near that of sea water.

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