Egg capsules.
Left: T. reticulata, Anglesey, Wales, May 2016.
Right: T. nitida, Oosterschelde, Netherlands, August 2019, © B. van der Sanden.
T. reticulata egg capsule initially has a circular chamber, and ova fill c.50% of it (top left).
Later the capsule broadens as the ova grow to fill it (bottom left). Mean height 4.07 mm, width 3.25 mm.
The chamber in T. nitida egg capsules is ovoid, taller than broad. Mean height 2.65 mm, width 1.72 mm (Roland & Luque, 1994).
‘Recognition of T. nitida’ article. below 01 01 Tritia nitida COMPARISON T. reticulata