STELLATE OBJECTS FOR THE
MICROSCOPE
by Brian Darnton & Wim van
Egmond
Radiolaria
Radiolaria. Although not uncommon in the seas of the world these are not stranded on the beachline as are other organisms. This is probably because they are siliceous in nature, unlike the Foraminifera and some sponge spicules which are calcareous. This image is from the fossil deposits of Springfield Barbados West Indies, and must be seen in dark-ground illumination. Central black patches of increasing diameter may be tried in the centre of the sub-stage filter holder until all direct light is excluded but the object remains brightly illuminated by oblique light from the sub-stage condenser. The sub-stage iris needs to be wide open.