A similar membrane can easily be shown, to surround the fæcal pellets of calanoid copepods, where it often forms a ‘tail’, occasionally of considerable length, at each end of the pellet.

Razorfish prey usually consists of small invertebrates, like amphipods and copepods. These tiny crustaceans sometimes like to make their home in sea urchin spines but, thanks to the razorfish’s ...