The present study investigates the physioIogical bases of species which compose the typical vegetation types of the Northern Namib: the savannas, the subtropical grasslands and the succulent deserts. The relative role in terms of vegetation cover and species diversity of the various pathways of photosynthetic production is determined and the environmental factors responsible for the distribution of the various metabolic types is discussed.
Up to two conglomerate layers carrying specimens of Striostrea margaritacea are interbedded in a layered deposit of unconsolidated and gypsum-cemented sand which occurs up to 50 m above sea-level. Size distribution analysis of the sand and surface characteristics of the sand grains indicate sheet- flood action and rapid buriaI, but aeolian and marine reworking is evident and mixing of fluviatile, aeolian and marine sand populations occurred in a fluviomarine environment. The Iittoral fauna suggests freely circulating sea water during periods of limited detrital supply.
Five out of seven P. ruber were handed-reared to the flying stage on artificial diet. Mortality was due to secondary pulmonary infection, probably arising from food particles accidentally entering the respiratory tract. Two of the survivors were hatched in captivity, the remainder being up to four days old when captured.
The breeding of the Damara Tern Sterna balaenarum near Swakopmund, South West Africa, is descriptionbed. Loose aggregations of nesting birds occur on gravel plains about one kilometre inland from the sea.
The Europian Marsh Warbler Acrocephalus palustris was recorded for the first time in South West Africa. From a number of birds found in the study are east of Windhoek, two individuals were collected. A third individual was ringed. Song and habitat are descriptionbed. Measurements are given and moult is descriptionbed.
A geological survey of the area shown in Figure 1 was carried out between February and June 1973. The area comprises 560 square kilometres and was traversed on 43 lines, each 1 kilometre apart and at right angles to the southeast boundary. Birds were counted on the traverses and groups mostly of four adjacent traverses were synthesised into trancepts.