Text-fig. 5. Auckland. Monthly average air temperatures. 1. Absolute highest maximum. 2. Mean highest maximum. 3. Mean lowest minimum. 4. Absolute lowest minimum. concerning the main current systems affecting New Zealand shores. It was shown that such bottles could travel over 6,400 kilometres, averaging a speed of 13 km. per day (ranging from 2.2 to 21.3 km. per day according to wind strength and direction). The biological implications are important, for these results show that living organisms can travel from South America to New Zealand or Australia in under three years. It is doubtful, however, that algal germlings or fragments would survive for so long a period and still be in a sufficiently healthy state to compete successfully for establishment with those forms already dominating on Australasian shores. (b) Sea Temperatures A lag of about a month behind air temperatures is responsible for the highest records occurring in February and the lowest in August. Minimum records off the east coast of the North Island are appreciably higher than those of the west. From August there is a gradual increase, differences between east and west coasts becoming negligible. The warmest months are from January to March, during which time sea temperatures remain almost constant. Throughout the years 1949 and 1950 when the field work of this survey was carried out, sea temperatures were in general 1–2° C. higher than normal, as indicated by M.O.M. (Meteorological Office Memoirs) figures. These warmer temperatures were most evident in the north Tasman and off the east coast of both North and South Islands. The increase in the north Tasman may be attributed to a stronger and more easterly flow of the East Australian Current. Warmer water on the east coast appeared to be due to a more southerly penetration of the East Cape Current. Despite their derivation from records of ships over a considerable period of years, M.O.M. charts of mean currents do not present a uniform pattern either in the Tasman or to the east of New Zealand; but data assembled for the year 1949 indicate that waters carried in a westerly direction by trade winds are deflected