900 PRINCIPAL SIR WILLIAM TURNER ON 
The facial part of the skull formed the rostrum, or beak, highly arched from behind for- 
wards. The superior maxila articulated at its nasal end with the frontal ; it widened 
laterally into a triangular plate which passed downwards and outwards parallel to 
and in front of the strong bar of the frontal. The plate did not overlap the outer 
surface of the frontal, but was prolonged below its deeper surface, and ended externally 
in a pointed apex 6 inches internal to the pre-orbital process of the frontal. Near the 
base of the plate the bone was pierced by five large foramina for the transmission of 
vessels and nerves to the beak. The superior maxilla formed the outer border of the 
rostrum to within 6 inches from the tip; it diminished in breadth from behind forwards, 
and its anterior end was about an inch broad; its upper surface was longitudinally 
grooved in the greater part of its extent. The base of the beak was not, as in the 
Odontoceti, definitely marked by a notch, but was indicated approximately by the most 
posterior of the large vascular foramina; it was about 3 feet broad. 
The premaaille extended from the frontal at the vertex to the tip of the beak; 
they were arched from behind forwards, and convex from side to side. In breadth each 
bone attained a diameter of from 8 to 9 inches, and as they were longer and broader 
than the superior maxillee they formed the more noticeable constituents of the beak. 
A horizontal line drawn from the edge of the glenoid cavity to the tip of the beak 
formed the chord of the are of the beak, and a perpendicular drawn from it to the 
outer border of the highest part of the arch of the superior maxilla measured 34 feet. 
The nasal bones were locked between and articulated with the premaxille and the 
frontal. Their long axis was almost horizontal, the upper surface was flattened, the 
under surface entered into the roof of the nose, the thickened posterior border was in 
line with the upper ends of the superior and pre-maxille, the anterior border was 
slightly concave and had a short projection at its mesial angle. 
The anterior nares opened forwards in front of the nasals, their antero-posterior 
diameter was somewhat more than 2 feet, and their greatest breadth a little in front of 
the nasals was more than 1 foot ; each side was formed by the inner surface of the 
premaxilla. On looking into the nares an ethmoido-turbinal was seen on each side, 
the anterior border of which was about 14 foot behind the anterior border of the nasal. 
The vomer was not a mesial plate at the anterior nares, but was spout-like in form ; its 
two lateral borders articulated with the premaxillz, and its mesial groove lodged a thick 
band which represented a mesethmoid. 
The hard palate had a strong mesial keel formed by the vomer, which was visible 
between the palatal surfaces of the superior maxillee to within about 4 feet from the tip 
or the beak. The keel divided the palate into two equal lateral halves, each of which, 
concave from side to side and from before backwards, contained foramina for vessels and 
nerves to supply the palatal mucous membrane and the baleen plates.* The hard palate 
along the curve was nearly 13 feet long, and its greatest breadth, measured in a straight 
* For an account of the structure and vascularity of whalebone, see my memoir on Balenoptera sibbaldi in 
Trans. Roy. Soc. Edin., vol: xxvi., 1870, 
