Zetterstedt, 1838
Body
Medium sized larvae up to 7 mm long. The posterior parapods bear only simpel claws (Wiederholm, 1983).
Head
S3 is simpel.
Antenna
The antenna stands on a tall smooth pedestal and consists of 5 segments. The basal segment is much longer than the flagellum Tatars antenna. Segment 2 is cylindrical and longer than the remaining segments. The pedestals of the small Lauterborn organs reach far beyond the antennal apex.
Mentum
In C. ambigua 3 median mental teeth and 1-2 pairs of lateral teeth situated dorsally behind the median teeth Cor ambigua mentum small. The ventromental plates are close together medially and wider than the mentum.
Labrum
SI is a comb and labral lamellae a single plate with numerous apical teeth. The pecten epipharyngis consists of 3 smooth plates with distal teeth. The premandible has 5 teeth.
Mandible
The mandible has no teeth Cor ambigua mandible.
Differential characteristics
The mentum is distinctive in having a central and dorsal part with only 1-2 pairs of teeth Cor ambigua mentum small.
The mentum is distinctive for the genus in having a central and dorsal or lateral part with only 1-2 or 4 pairs of teeth Cor ambigua mentum small.
C. ambigua is distictive by the mandible without teeth and the mentum strongly bend backwards.