"Fig 66 - Head of a chick, second stage, after five days of incubation, section in profile; x6 diameters. cvl, cv2, cv3, first, second, and third cerebral vesicles; 1, place of the first nerve, the olfactory; 2, place of second nerve, the optic; ic, internal carotid artery, running into skull at what was originally the pituitary space, now an opening bounded in front by the anterior, acl, behind the posterior, pcl, clinoid walls; nc, notochord; oc, occipital condyle, thence to pcl being the original parachordal cartilage, here seen in profile; eo, exoccipital; eth, ethmoid, with ps, its presphenoid region posteriorly, and pn, pre-nasal part; this whole plate afterward developing into parts of the nose and the partition between the eyes; pa, palatine; pg, pterygoid region; pa and pg reference lines are in the chick's mouth; mk meckelian cartilage (lower jaw); ch and bh, ceratohyal and basihyal parts of the hyoid or tongue bone." Elliot Coues, 1884

Chick Head

"Fig 66 - Head of a chick, second stage, after five days of incubation, section in profile; x6 diameters.…