Convoluted spawn. Left: from Alder & Hancock. Right: Barra, Scotland, © J. Anderson.
The spawn is a broad ribbon attached by its edge to the prey organism or substrate in a spiral of two or three turns, which may be tight and neat (Picton & Morrow) initially, later becoming convoluted, as above. Each spawn mass has up to 145 000 ova. Spawning has been recorded from February to August in Britain and to September in the Bay of Biscay. Veliger larvae spend about 23 days at 10ºC in the plankton before metamorphosis (Thompson & Brown, 1984).
45 Jorunna tomentosa
