Haeckel
Diagnosis: Radial tubes cylindrical to somewhat tapered distally, slender, straight or slightly curved. Terminal branches of the tubes very variable in size and number (2 to 6, usually 3 to 4), without lateral teeth or terminal spathillae, slender, conical, slightly curved, directed outwards, 2 to 4 times (rarely 5 to 8 times) as long as the breadth of the tubes. The number and size of the simple terminal branches is extraordinarily variable, even within the same specimen.
Length of tubes: 0.5-1.5 mm.