Longitudinal row of solitary cerata on each side of body; number in row increases with growth to eight or more.
Cerata are translucent whitish, revealing internal digestive gland which extends almost to the apex. Colour of digestive gland probably reflects diet; juveniles may feed on hydroid species different from those eaten by adults. No cnidosacs in cerata.
Cerata on juveniles lack, or have weakly developed, tubercles, surface pigment and internal red spheroids.