(Walker, 1856)
Body
Medium sized to large larvae up to 13 mm long. Living larvae red. Medium sized claws on anterior parapods with relatively blunt teeth Figuur 10 Morozova9. Claws on the posterior parapods are simpel. No lateral and ventral tubules (Wiederholm, 1983; Moller Pillot, 1984a).
Head
The gula and the ventral occipital margin are pigmented Gula pigmented9.
Antenna
The antenna consists of 5 segments. The basal segment is al long as or longer than the flagellum. Lauterborn organs are absent Cryptoch antenna 8.
Mentum
The mentum has one broad yellow median tooth and 6 pairs of lateral teeth. The outer tooth may be subdivided Cryptoch mentum 8. The ventromental plates as wide as or wider than the mentum and tapering lateraly. The striae are fine and simpel Figuur 12 Vallenduuk.
Labrum
SI is simpel and labral lamellae are absent Cryptoch labrum. The pecten epipharyngis consists of three lobes with a serrated margin. The premandible has 4-6 apical teeth.
Mandible
The mandible without a dorsal tooth. Apical tooth with 2 inner teeth. The pecten mandibularis is absent and seta interna with 4 branches, 2 smooth and 2 plumose.
Differential characteristics
The yellow median tooth, fused with the first of the six pairs of brown lateral teeth is distinctive for the genus Cryptoch mentum 8.
C. obreptans and C. supplicans have a pigmented gula. C. obreptans can be separated from C. supplicans by the following combination:
Length 1st antennal segment 70 - 115 µm (C. supplicans 70 - 95 µm); S3 - S3 = 45 - 75 µm (60 - 90 µm in C. supplicans) and (S3 - S3)/ length 1st antennal segment 0.53 - 0.83 µm (0.78 - 1.06 µm in C. supplicans). Also the medium sized claws on the anterior parapods are relatively blunt Figuur 10 Morozova9.