1. The present paper is a direct continuation of the work done at Millport during 1926 and 1927.

2. As before, Tellina tenuis showed no growth during the winter months.

3. As before, the rate of growth at L.W.M. was less than that near H.W.M.

4. Below L.W.M. there seemed to have been no growth during the year, but there had been a heavy mortality during 1928.

5. Above L.W.M. the rate of growth during 1928 was of the same order as that of 1927, and the view that a year group was unrepresented on the 1926 curve seems justified.

6. At the end of September, 1928, the 1926 spat still formed a large and well-marked group.

7. The history of the 1926 spat is traced, and the annual increment found to be halved in succeeding years.