A display entitled "Pilgrim Geese," with three geese in cages.

Three ponds were chosen for this study. The two lower ones were of 2 - 4 hectares in area, the depth of the littoral zone was 2.5 - 3 metres at the time of maximum flooding and the mud which covered the floor of the ponds was homogeneous and autochthonous in nature with very few vegetable remnants. The ponds which were originally set up in 1950. were intended for water supply and populated with Crucian Carp (for human consumption). A survey was done in the ponds in order to establish number and biomass of Tendipes semireductus. The author concludes that in these ponds T.semireductus has 2-3 generations per year. | Translated from Russian into English

Flowering of the SD plant Perilla crispa was also possible in LD and in continuous light, if lighting was weak enough. The light range within which flowering is possible, decreased with increasing day length. With an illumination of 300μwatts/cm 2spherical cross-section, seedlings were day-neutral. Older plants proved more predisposed to flower than seedlings. In plants with two equivalent but differently illuminated shoots the brightly lit shoot initiated flowers in long days through influence of the weakly lit shoot; this influence was stronger after defoliation of the brightly lit shoot. Neither in bright nor weak light (with SD or LD) did defoliation qualitatively influence flower initiation. Even 0.5 cm leaf surface was sufficient for flower initiation.With the day-neutral tomato (Lycopersicum esculentum var. Ailsa Craig) defoliation advanced flower initiation and increased the number of flowers. Brighter light decreased the number of leaves before the initiation of the first flower cluster; in very weak light the plants could be kept vegetative for a year.With the day-neutral Phaseolus vulgaris var. Vroege Wagenaar defoliation of the main shoot promoted development of axillary shoots, through whose later defoliation the number of flowers could be increased. There was a positive correlation between flower number and light intensity. Flower initiation itself was however independent of intensity, day length, removal of cotyledons or defoliation but the number of flowers decreased through removal of the cotyledons.In SD plants too much growth regulator probably inhibited flowering; in other plants this was caused by the growing leaf. Flowering probably needed an equilibrium between available assimilates and growth regulators.

Flowering of the SD plant Perilla crispa was also possible in LD and in continuous light, if lighting was weak enough. The light range within which flowering is possible, decreased with increasing day length. With an illumination of 300μwatts/cm 2spherical cross-section, seedlings were day-neutral. Older plants proved more predisposed to flower than seedlings. In plants with two equivalent but differently illuminated shoots the brightly lit shoot initiated flowers in long days through influence of the weakly lit shoot; this influence was stronger after defoliation of the brightly lit shoot. Neither in bright nor weak light (with SD or LD) did defoliation qualitatively influence flower initiation. Even 0.5 cm leaf surface was sufficient for flower initiation.With the day-neutral tomato (Lycopersicum esculentum var. Ailsa Craig) defoliation advanced flower initiation and increased the number of flowers. Brighter light decreased the number of leaves before the initiation of the first flower cluster; in very weak light the plants could be kept vegetative for a year.With the day-neutral Phaseolus vulgaris var. Vroege Wagenaar defoliation of the main shoot promoted development of axillary shoots, through whose later defoliation the number of flowers could be increased. There was a positive correlation between flower number and light intensity. Flower initiation itself was however independent of intensity, day length, removal of cotyledons or defoliation but the number of flowers decreased through removal of the cotyledons.In SD plants too much growth regulator probably inhibited flowering; in other plants this was caused by the growing leaf. Flowering probably needed an equilibrium between available assimilates and growth regulators.

Calculated milk productions for 89 Jersey cows based on yield recordings made at weekly, fortnightly and monthly intervals were compared with actual production. The results indicated that in experiments involving the production of a small number of cows, the shortest recording interval that could be used to ensure a reasonable degree of accuracy would be one week. A longer interval would be suitable where a large number of cows was involved and the recordings averaged, as the plus errors would then tend to cancel out the minus errors.

A number of cases of infection of the kidneys in birds by trematodes of the genus Renicola Cohn, 1904 is reported and two new species of the genus are described. One of them, Renicola pelecani sp. n., has been found in both the White Pelican (Pelecanus onocrotalus) and the Spot‐billed Pelican (Pelecanus phillipensis). The other, Renicola sloanei sp. n., has been found in a number of species of penguin. It has also been found in a Common Guillemot (Uria aalge) from Sussex, this being the first record of a Renicola from a wild bird in Great Britain.