Thickness, C, D, from the angle of the lower jaw to the anterior surface (a half-head), 0·30 metre. This line passes through the middle of the eye, taken perpendicularly, to the profile of the anterior surface. Many common horses present it, especially the heavier draught horses; in finely-bred subjects it is a little shorter (G. and B.).
Depth, I, H, of the neck in its narrowest part (a half-head), 0·30 metre. It is frequently greater; this is noticeable in all instances where the superior parts of the neck are deficient in fineness. It is this which we see in draught horses, and in those which become too fleshy (G. and B.).
Distance, O, R, of the internal commissure of the eye from the superior border of the commissure of the nostril (G. and B.) (a half-head), 0·30 metre. It is more considerable on the common head, and on that which is too long.
Distance, A, O, from the nape to the internal angle of the eye, 0·22 metre. This distance is equivalent to the thickness of the head, P, Q, taken perpendicularly from the profile of the anterior surface, and passing at the level of the maxillary fissure and spine.
It is, again, equal to Q, O, from the internal angle of the eye to the maxillary fissure; and to P, G, from the middle of the face to the commissure of the lips (G. and B.).
The distance, P, E, from the middle of the face to the maxillary spine is about the sixth of the total length of the head—0·10 metre.
The line B, E, reckoned from the extremity of the lips to the maxillary spine, is equal:
To E, F, from the maxillary spine to the external auditory meatus, to be seen only on the skull;
To H, G, from the insertion of the neck in the trough to the commissure of the lips (G. and B.);
To Q, R, from the maxillary fissure to the superior commissure of the nostril (G. and B.);