In ovo Experiments Concerning the Eye, the Orbit, and Certain Juxta-Orbital Structures, in the Chick Embryo
The present communication concerns the influence in the chick (Gallus domesticus) of the growing eyes on various structures which form the wall of the orbits, or which lie in their vicinity. Features of the development of the trabeculae cranii, the fronto-nasal process, the nasal capsules, the maxillary ‘process’, the otic capsule, and the cephalic flexure will be described as well as certain growth relationships of the upper and lower jaws. The methods employed include (1) removal of one or both primary optic vesicles, (2) the grafting of an additional primary vesicle into the head mesenchyme so that two eyes develop in one orbit, and (3) the isolation in the coelom of various head components. The importance of the trabeculae to our present study stems from the fact that they contribute to the boundaries of the orbits on their medial sides.