GOO 
lME, TV. K. PARKER OK THE STRUCTURE ARD 
This is the swfr-orbital “ os terminate,” whilst the nasal is “ the super-orbital “ os ter¬ 
minate they were, in the Fish-class, the two end bones of the lateral-line “ forkover 
the eye and under the eye ; the “supra-temp orals ” joined these to the “ post-temporals/ 
or foremost lateral-line bones of the trunk. (See “ Shoulder-girdle and Sternum,” 
Plates 1 and 2, pp. 10-57.) 
The upper jaws and cheek bones belong to a lower category of scutes arising, in the 
body, below the bones of the lateral-line ; they are the highest of the infero-lateral 
series; the splints of the lower jaw belong to the sub-mesial ventral series. 
When the axis is developed largely in front of the mouth, there then may be (as in 
Acipenser, but much more in Polyodon ) a long series of ventral and sub-ventral bones 
under the “rostrum.” 
These, as Mr. Bridge’s valuable paper shows, are constantly showing (as in the dorsal 
region of the head) an alternation of azygous with paired scutes or plates. 
In the Lizard even, and still better in birds with a double vomer, this is seen; 
in the latter we have two vomers, then one parasphenoid, and two basi-temporals : just 
a miniature of what is seen under the “ rostrum ” of Polyodon. Truly, a marvellous 
instance of atavism ! 
The pram axillary (px.) forms a key-stone to the arch of the upper jaw; it is rather 
small, rounded in front, dentigerous, has a flat acuminate nasal process, and a seed¬ 
shaped palatine process. Here it is single ; in some Lizards, as Cyclodus, there are two. 
The maxillaries are developed almost as much as in some of the lower Mammalia, 
and far more than in most birds where the prsemaxillaries are prepotent. 
Each large toothed bone (mx.) well walls in the fore face; it runs up high, touches 
the frontal, and wedges in between the nasal and prefrontal. 
Below, inside the wide alveolar region, there is a distinct palatal selvedge, which binds 
under the vomer and palatine (tig. 2, u, pa.). 
The outer nostril with its valve of cartilage is neatly walled round by the pre¬ 
maxillary, maxillary, and nasal (figs. 1 , 3 , px.,‘mx., n., e.n., ol.). 
The orbit is finished below by the cheek bone or jugal (J .); this is set obliquely on 
to the jugal process of the maxillary, along which it runs, as a fine style, up to the 
small, perforate, sunken lachrymal (/.). 
Behind, it sends backwards a free snag, and then gradually narrows upwards, and is 
attached to the lesser and greater post-orbitals (fig. 3). There the cheek series ends, so 
that we miss the quadrato-jugal, which is only present in the Lacertilia in Hatteria, 
although constant in Tortoises and Crocodiles. 
In this region, as in many others, the Bird bears hereditary marks of some very 
generalized fore-parents, whose dermal armature was composed of many plates. 
In not a few birds—Emu, Barn Owl, Heron, Cormorant, &c. —there is a “ post¬ 
maxillary,” besides the quadrato-jugal and jugal, making four bones in the jugo- 
maxillary chain, and reminding the morphologist of Lepidosteus. 
In the Batrachia, where the cheek is bound on to the suspensorium for the first time, 
