"Diagram showing the ear and related parts in a young cat. P., Pinna; Sq., squamosal: E.A.M., external auditory meatus; T., tympanum; M., malleus; I., incus; St., stapes abutting onforamen ovale; B., bulla of tympanic bone; Se., a septum in the bulla; E.T., eustachian tube leading from the tymmpanic cavity to the back of the mouth; B.O., basi-occipital; C., cochlea; S., sacculus; U., utriculus; D.E., ductus endolymphaticus; N., auditory nerve; S.C., semi-circular canal; PE., periotic bone." -Thomson, 1916

Cat Ear

"Diagram showing the ear and related parts in a young cat. P., Pinna; Sq., squamosal: E.A.M., external…

"Ripe chick's skull, longitudinal section, vied inside, x 3 diameters; after Parker. px, premaxillary; aln, ali-nasal cartilage; en, septo-nasal; n, nasal bone; l, lacrymal; pe, perpendicular plate of ethmoid, ps, prespeenoidal region; as, alisphenoid; f, frontal; p, parietal; sq, squamosal; so, superoccipital; eo, exoccipital; oc, occipital condyle; st, the cross-like object, the stapes, whose foot fits fenestra ovalis; q, quadrate; pg, pterygoid; qj, quadrato-jugal; jugal; pa, palatine; mx, maxillary. In the mandible: d, dentary; su, surangular; a, angular; ar, atricular; iap, internal angular process; pap, posterior angular process. 2, optic foramen; 5, foramen ovale, for inferior divisions of the 5th nerve." Elliot Coues, 1884

Ripe Chick's Skull Profile

"Ripe chick's skull, longitudinal section, vied inside, x 3 diameters; after Parker. px, premaxillary;…

"Ripe chick's skull, longitudinal section, vied inside, x 3 diameters; after parker. In the mandible are seen: mk, remarks of meckelian rod; d, dentary bone; sp, splenial; a, angular; su, surangular; ar, articular; iap, internal articular process; pap, posterior articular process. In the skull: pn, the original prenasal cartilage, upon which is moulded the premaxillary, px, with its nasal process, npx, and dentary process, dpx; sn, septo-nasal cartilage, in which is seen nn, nasal nerve; ntb, nasal turbinal; the reference line crosses the cranio-facial suture, the face parts and cranial parts being nealry separated here by the nick seen in the original cartilaginous plate; eth, ethmoid; pe, perpendicular plate of ethmoid, which will spread nearly throughout the dotted cartilaginous tract in which it lies, to form nearly all the interorbital septum; transverse thickening (in some birds) below the reference line eth will form the pre-frontal, or orbito-nasal septum; iof, inter-orbital foramen; ps, pre sphenoidal region, just above which is the orbito-sphenoidal region; 2, optic foramen; as, alisphenoid, with 5 foramen for division of the 5th (trifacial) nerve; f, frontal; sq, squamosal; p, parietal; so, superoccipital; asc, anterior semicircular canal; sc, a sinus (venous canal); ep, epiotic; eo, exoccipital; op, opisthotic; po, prootic, with 7 meatus auditorius internus, for entrance of 7th nerve; 8, foramen nfor vagus nerve; bo, basioccipital; bt, basitemporal; ic, canal (in original pituitary space; ) by which carotid artery enters brain activity; ap; basipterygoid process; ap to rbs, rostrum ofhte skull, being the parasphenoid bone underflooring the basisphenoid and future perpendicular plate of ethmoid." Elliot Coues, 1884

Ripe Chick's Skull

"Ripe chick's skull, longitudinal section, vied inside, x 3 diameters; after parker. In the mandible…

"Fig. 62 Skull of common fowl, enlarged. from nature by Dr. R.W. Shufeldt, U.S.A. The names of bones and some other parts are printed, requiring no explanation; but observe the following points: The distinction of none of the bones composing the brain-case (the upper back expanded part) can be found in a mature skull. The brain is contained between the occipital, sphenoidals, squamosals, parietals and part of frontal; the ethmoidals belong to the same group of cranial bones proper. All other bones, excepting the three otic ear-bones, are bones of the face and jaws. The lower jaw, of five bones, is drawn detached; it articulates by the black surface marked articular with the prominence just above- the quadratic bone. Observe that from this quadrate a series of bones quadrato-jugal, jugal, maxillary-makes a slender rod running to the premaxillary; this is the zygoma, or jugal bar. Observe from the quadrate also another series, composed of pterygoid and palatine bones, to the premaxillary; this is the pterygo-palatine bar; it slides along a median fixed axis of the skull, the rostrum, which bears the loose vomer at its end. The under mandible, quadrate, pterygoid, and vomer are the only movable bones of this skull. But when the quadrate rocks back and forth, as it does by its upper joint, its lower end pulls and pushes upon the upper mandible, by means of the jugal and pterygo-palatine bars, setting the whole scaffolding of the upper jaw in motion. This motion hinges upon the elasticity of the bones of the forehead, at the thin place just where the reference-lines from the words "lacrymal" and "mesethmoid" cross each other. The dark oval space behind the quadrate is the external orifice of the ear; the parts in it to which the three reference-lines go are diagrammatic, not actual representations; thus, the quadrate articulates with a large pro-otic as well as with the squamosal. The great excavation at the middle of the figure, containing the cirlet of the unshaded bones, is the left orbital cavity, orbit, or socket of the eye. The mesethmoid includes most of the background of this cavity, shaded diagonally. The upper one of the two processes of bone extending into it from behind is post-frontal or sphenotic process; the under one (just over the quadrate) is the squamosal process. A bone not shown, the presphenoid, lies just in front of the oval black space over the end of basisphenoid. This black oval is the optic foramen, through which the nerve of sight passes from the brain-cavity to the eye. The black dot a little behind the optic foramen is the orifice of exit of a part of the trifacial nerve. The black mark under the letters "on" of the word "frontal" is the olfactory foramen, where the nerve of smell emerges from the brain-box to go to the nose. The nasal cavity is the black space behind nasal and covered by that bone, and in the oval blank before it. The parts of the beak covered by horn are only premaxillary, nasal, and dentary. The condyle articulates with the first cervical vertebra; just above it, not shown, is the foramen magnum, or great hole through which the spinal medulla, or main nervous cord, passes from the spinal column. The basioccipital is hidden, excepting its condyle; so is much of the basisphenoid. The prolongation forward of the basisphenoid, marked "rostrum," and bearing the vomer at its end, is the parasphenoid, as far as its thickened under border is concerned. Between the fore end of the pterygoid and the basisphenoidal rostrum, is the site of the basipterygoid process, by which the bones concerned articulate by smooth facets; further forward, the palatines ride freely upon the parasphenoidal rostrum. In any passerine bird , the vomer would be thick in front, and forked behind, riding like the palatine upon the rostrum. The palatine seems to run into the maxillary in this view; but it continues on to premaxillary. The maxillo-palatine is an important bone which cannot be seen in the figure because it extends horizontally into the paper from the maxillary about where the reference life "maxillary" goes to that bone. The general line from the condyle to the end of the vomer is the cranial axis, basis cranii, or base of the cranium. This skull is widest across the post-frontal; next most so across the bulge of the jugal bar." Elliot Coues, 1884

Skull of a Common Fowl

"Fig. 62 Skull of common fowl, enlarged. from nature by Dr. R.W. Shufeldt, U.S.A. The names of bones…

"Side view of skull of horse, with the bone removed so as to expose the whole of the teeth. PMx, premaxilla; Mx, maxilla; Na, nasal bone; Ma, malar bone; L, lacrymal bone; Fr, frontal bone; Sq, squamosal bone; Pa, parietal bone; oc, occipital condyle; pp, paroccipital process; i, the three incisor teeth; c, the canine tooth; pm1, the situation of the rudimentary first premolar, which has been lost in the lower, but is present in the upper jaw; pm2, pm3, and pm4, the three fully-developed premolar teeth; m, the three true molar teeth." — Encyclopedia Britannica, 1893

Horse Skull

"Side view of skull of horse, with the bone removed so as to expose the whole of the teeth. PMx, premaxilla;…

"Skull of Polyodon. n, nasal cavity; sq, squamosal; mh, hyomandibular; sy, symplectic; pa, palate-pterygold; m, Meckelian cartiledge; mx, maxillary; d, dentary; h, hyoid; op, operculum; br, branchiostergal; s.cl, supraclavicular; p.cl, postclavicular; cl, clavicle; i.cl, infraclavicular." — Encyclopedia Britannica, 1893

Polyodon

"Skull of Polyodon. n, nasal cavity; sq, squamosal; mh, hyomandibular; sy, symplectic; pa, palate-pterygold;…