Differences in external morphology can been seen through
image searches, though from observed specimens on Heron Island and historical documentation (Carter, 1883; Pulitzer-Finali, 1993; Kennedy, 2000), most display a globular, spherical shape with apical depressions 0.5-5cm deep in which clusters of oscules are focused. A detailed description can be found
here.
Image: (above) Rhabdastrella globostellata specimen in field on Heron Island, 2011.
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Image: (above) Rhabdastrella globostellata specimen in the research station's holding tank on Heron Island, 2011. Note the apical depressions with clusters of oscules set inside. (below) The same sample from a different angle. The oscules appear to form at one end of the sponge, most likely the "top" orientation when specimen was in situ.
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