ABSTRACT
A study of the rather scarce and widely scattered literature concerning the respiratory exchange of Lamellibranchia shows that even under constant external conditions the oxygen intake of a given specimen is extremely variable. This phenomenon was observed by Mitchell (1912) and Galtshoff and Whipple (1930) in Ostrea, by Weinland (1918) in Anodonta, by Collip (1921) in Mya, by Bruce (1926) and Bouxin (1931) in Mytilus.
Cutaneous respiration is here left out of consideration.
When trying to check my micromethod with the macromethod of Winkler, also in the case of sea water, I was unable to attain a full agreement; the cause of this discrepancy is not yet clear, but since the individual trials of the micromethod corresponded very closely, it does not invalidate the results of my experiments. It must, however, be borne in mind that all oxygen figures given in this paper may be from i to 4 per cent, too low.
The Chinese ink apparently did not irritate the animal.
All determinations concerning utilisation were performed on the same specimen.
That this phenomenon is not due to an initially high and then gradually diminishing CO2 content of the anal water (the CO2 reacting with the Mn” of the MnCl2, solution, thus forming MnCO3 which does not react with oxygen) was shown by adding a threefold quantity of reagents ; in this case the same results were obtained.
The three experiments represented all show a slight irregularity at the beginning. I do not know whether this temporary increase of the utilisation is a coincidence or not. These irregularities are obviously too great to be accounted for by the inaccuracy of the method for determining the oxygen content as such.
Some other conclusions reached by Jatzenko are open to objection, as, for example, where it is stated that the circulatory system of Lamellibranchia has external outlets (cf. Quagliariello, 1925), and that the haemocyanin is contained in and the O2 is transported by the amoebocytes.
