The first stage of complication is by the development of cartilage in the notochordal sheath, as in Petromyzon.
The vertebrae are nearly always amphicoelous and sometimes have notochordal centra.
In some forms however, like Euchirosaurus, the centra are imperfectly ossified, and consist of bony rings traversed by a wide notochordal canal.
Its cells become highly vacuolated and take on the typical notochordal structure[21].
Between this sheath and the notochordal tissue a thin layer of lining cells, of normal appearance, is conspicuous in Ammocoetes.
Notochordal tissue has no resemblance to bone or cartilage, or any of the usual supporting tissues.
These cells secrete the layers of the sheath, and have originally, by proliferation, given rise to the notochordal tissue.
These vertebrae were confined to the notochordal part of the skull, the prechordal part having arisen secondarily from the vertebral part, while the number of vertebrae are at least nine, possibly more.
With cessation of its function its cells became vacuolated, as in these other cases, and its lumen became filled withnotochordal tissue.
In the stage between the two it may well have opened into an intermediate gut, the notochordal tube, its separation from which would leave the end of the {441}notochord blind, just as it had already left the end of the infundibulum blind.
The notochordal tube is unsegmented, although the vertebrate is markedly segmented.
In the second group the vertebrae have their calcareous matter arranged in rings, one or more about the notochordal center.
Through the vertebral region, shewing the neural and haemal arches, the notochordal sheath, &c.
During this stage the protoplasm of the notochordal cells, which in the last stage formed a kind of axial rod in the centre of the notochord, begins to spread outwards toward the sheath of the notochord.
The anterior wall of this passage connects together the medullary plate and the notochordal ridge of the hypoblast.
In Teleostei there is present, as in Elasmobranchii, an elastica externa, and an inner notochordal sheath.
As soon however as the notochordal sheath was required to be strong as well as flexible, it necessarily became divided into a series of segments.
In the early stages of development the spaces in the notochordal sponge-work, each containing a nucleus and protoplasm, probably represent cells.
He holds that the inner layer corresponds to the cartilaginous notochordal sheath of the lower types, and the outer to the arch tissue.
Longitudinal section through the notochord and adjoining parts to shew the first appearance of the cartilaginous notochordal sheath which forms the vertebral centra.
Probably the whole posterior surface of the braincase slanted posteroventrally; consequently the rim of the notochordal canal was about 3.
In posterior view the notochordal canal and foramen magnum are confluent with each other, and of great size relative to the skull as a whole.
The rounded intercentrum in both is an incomplete ring enclosing the notochordal canal.
The U-shaped border of the notochordal canal is a thick, rounded bone, comparable in appearance to the U-shaped intercentra of the vertebrae.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "notochordal" in a variety of sentences. We hope that you will now be able to make sentences using this word.
