Brachionus calyciflorus (amphiceros ?), with egg on left
A very large, robust live rotifer. It measures over 250µ in length not including the spines. Sample collected from Back River near Baltimore, July 2003.
Rotifers are sometimes difficult to fix; they tend to close up making identification difficult. Adding substances such as Protoslo, 30% magnesium chloride solution or seltzer water will slow them down and relax them for better observation.