27. The Chondrocranium of the Teleostean Fish Sebastes marinus.
- 1There is a precocious development of the visceral skeleton.
- 2In at least the earlier stages there is no sign of a fenestra hypophyseos.
- 3The cranial flexure is retained for a considerable period after hatching.
- 4In the 5·5 mm. stage the hyomandibular, symplectic, and quadrate are represented by a simple temporal cartilage. This appears also to be a single piece of cartilage in the earlier stages.
- 5The upper jaw does not appear until a comparatively late stage, and there is evidence that it arises independently and grows back to meet the quadrate.
- 6The anterior part of the trabeculæ gives rise to an interorbital septum of rather limited area.
- 7There is a free rostral cartilage situated above the nasal septum.
- 8The lower jaw is long and exhibits prominent coronoid and retro-articular processes.
- 9The hyomandibular is club-shaped and very long. Its length is correlated with the special depth of the head.