904 PRINCIPAL SIR WILLIAM TURNER ON 
The Petrous bone was fused in two places with the tympanic in B. mysticetus, 
biscayensis and australis: the more anterior was in front of the great oblique groove at the 
upper border of the anterior division of the outer surface ; the more posterior was fused 
with the upper part of the inner surface close to the opening into the tympanum. The 
periotic proper constituted a small proportion of the petrous, and was situated opposite 
and internal to the opening into the tympanum. It was formed of hard dense bone, and 
in B. mysticetus measured 23 inches by 12 inch; in biscayensis 23 by 12; in australis 
2% by 1g. The three species closely resembled each other in the characters of the periotic 
proper: the inner or cranial surface was jagged and marked by the canals or foramina 
for the auditory vessels and nerves; the outer or tympanic surface showed the fenestra 
ovalis for the stapes. The inferior surface of the petrous was relatively smooth; the 
superior surface was more spongy in character and articulated with the cranial wall. 
In mysticetus the so-called mastoid was 6 inches long, in biscayensis 44 inches, and in 
australis 84 inches. ° 
Two of the Tympanic ossicles were present in more than one specimen. The 
Malleus was fused with the lip-like process of the tympanic, the Incus articulated with 
the malleus, the Stapes was absent. 
The tympanic ossicles of the Taranto biscayensis were figured by CaPELLINI and 
Gasco in their respective memoirs on this animal, and the malleus and incus from one of 
my crania are figured in Plate III. fig. 15. 
VERTEBRAL COLUMN. 
I arranged the bones of the spine in groups with the bodies in contact with each 
other. The vertebral plates, with few exceptions, were either wholly or partially fused 
with their bodies; the intervertebral discs were fused with the cervicals, but were other- 
wise absent. The length of the spine from the atlas to the terminal caudal, in a straight 
line, was 26 feet 8 inches. Had the discs been in place the length would probably 
have been from 30 to 31 feet. The condition of ossification showed that the whale had 
reached maturity. ‘I'he vertebral formula was C,D,,LCd,,=56. ‘The vertebrae were 
weighty in relation to their size, as also in Balena mysticetus. 
Cervical Region.—The seven cervical vertebree with their discs were fused into a mass 
of bone, in which the constituent vertebrze could readily be recognised, though the fusion 
of the anterior six with each other was much more complete than that of the 6th with the 
7th, for in these two the osseous union was limited to their inferior or ventral surfaces, 
where an osseous outgrowth united the two bodies (Plate II. fig. 6). The length of 
the cervical mass, measured on the ventral aspect, was 13 inches, the greatest width 
between the tips of the transverse processes of the atlas was 2 feet 3 inches. The 
anterior surface of the atlas possessed two separate articular concavities for the occipital 
condyls, the diameter between their outer borders was 14 inches, and the vertical 
diameter of each was 11 inches. The spinal foramen was 5+ inches broad and 7 inches 
vertically. The spines of the anterior six cervicals were fused together, also the 
