The Skull of a Chick Stage Two

“Skull of chick, second stage, in profile, brain and membranes removed to show cartilaginous formations, X4 diameters. eth, ethmoid, forming median nose-parts and inter-orbital septum; developing lateral parts, as ale, aliethmoid, als, aliseptum, aln, alinasal, pp, partition between nose and eye; pn, prenasal cartilage; ps, presphenoidal part of midethmoid; 2, optic foramen; as, alisphenoid, walling brain-box in front; pf, post-frontal, bounding orbit behind; pa, pg, palatine and pterygoid; q, quadrate; so, supra-occipital; eo, ex-occipital; oc, occipital condyle, borne upon basi-occipital, and showing nc, remains of notochord; these occipital bound the foramen magnum, and eo expands laterally to form a tympanic wing, circumscribing the external auditory orifice behind and below; hsc, psc, horizontal and posterior vertical semicircular canals of ear; fr, st, fenestra rotunda and fenestra ovalis, leading into inner ear, latter closed by foot of the stapes; mk, ch, bh, bbr, cbr, ebr, parts of jaw and tongue.” Elliot Coues, 1884

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