Cuvier points out certain differences between the skulls of the Itorquals of the Cape, the Mediterranean, and the North Sea, for which we must refer the reader to his `Ossemens Fossiles.' Baltena.—To form the idea of a Balcena, properly so called, Cuvier states that we must figure to ourselves the muzzle of the ltorqual narrowed, elongated, compressed laterally, and arched from before backwards, nearly iu a quarter of a circle. It is, he observes, in tho space which this curvature leaves, that the plates of baleen, or whale bone, which adhere by their upper and wide extremity to the sides of the keel which the muzzle forms below, and descend obliquely outwards by their lower and pointed extremity towards the lower jaw, are lodged. It is precisely because this curvature gives them more space in the Bakens', properly so called, that they are longer in those whales than in the Rorquals, in which last the nearly straight muzzle leaves them little room.
It reittlta from this lateral compression of the muzzle that the intermaxillary bones are not horizontally between but vertically upon the maxillaries : the upper plane of these hat is itself nearly vertical, except. in the lateral branch, which borders the frontal before, to proceed with it upon the orbit. This transverse portion of the frontal bone is narrower from before backwards than in the ltorquaL The occipital bone is convex throughout its upper portion, less oblique than in the ltorqual, and semi-oval. The temporal bone remains transverse, and its zygomatic portion hardly curves forwards at all. The nasal bones are rhomboidal, and not triangular as in the Rorqual. Below, the palatine and pterygoidean bones are thrown still more back, and are shorter, and the sphenoid hone is more concealed thau in the Rorqual. The maxillary bone has a deep notch at its lower and posterior border. The glenoid surface of the temporal bone is much less vertical than in the Itorqual, so that tho lower jawbone rises a little to offer its articular convex surface. Thia disposition, joined to the absence of a coronoid apophyais, may serve to distinguish it from the lower jaw of the Rorqual.
In the Rorqual of the Cape, Cuvier found the atlas distinct from the axis; this hut is auchylosed by the upper part of its ring, which has no spinous apophysis, with tho corresponding part of the third cervical. This last and the four others do not unite : they are of some thickness. The transverse apophyses are double in the first three, AS in the axis; ono superior is given off from the annular portion below the articular apophysis, the other from the lower part of the body ; none of these apophyses are directed forwards. The lower are shortened from the axis to the fourth vertical and are wanting in the succeeding ones. The upper apophysea are longest on the axis and on the third ; afterwards they are equal, and form a series with the transverse apophyses which carry the ribs. There are 7
cervical vertebrae, 14 dorsal vertebrae and as many pairs of ribs, and 31 other vertebra to the end of the tail-52 in all. The second, third, and fourth ribs only have heads, and seem hardly able to reach the body of the vertebrae. The others only reach the extremities of the transverse apophyses, which go on lengthening to the lumbar region. They are longer than they are wide, and dilate at the end; as in the Greenland Whale. They thus continue to the thirteenth lumbar, where they begin to shorten, but still widen to the fifteenth or sixteenth, where they disappear. The spinous apophyses begin to show themselves on the third cervicaL They remain small on the neck, and begin to be elongated and compressed on the first dorsals. They form a nearly equal series; wider on the middle of the back, narrower, but always moderately elevated, ou the lumbar region, and shortening by degrees on the tail. They vanish on the last twelve, and the annular portion disappears two vcrtebrt after the spinous apophyses. The facets of the articular apophyses look inwards as far as the eleventh, where they begin to open outwards. They do not rise, and finally form, towards the fourteenth or fifteenth, with the spinous (which is always shortened), a trilobated prominence. The pelvis in the French skeleton is attached under the ninth lumbar vertebra. At the eleventh the V-shaped bones commence. The first is still formed of two separate bones. They re-divide anew behind. The lower part of the lumbar and caudal vertebrae is hardly marked by a slight carination. Commencing from the fifteenth vertebra after the dorsal, the body of each is pierced on both sides, above and below, with a large hole for the vessels. These holes do not diminsh on the last caudal, though they are much smaller, so that they each represent two cylinders set back to back, pierced in their axis.
The single bone of the sternum was square, deeply forked posteriorly, with a point at its external border.' The shoulder-blade of the Cape Rorqual is, Cuvier remarks, entirely different from that of the Bakena ; it is wider than it is long, semicircular on the spinal side, with a single anterior border, a singlo prominence (the acromion) towards the lower third, and a tubercle near the articulation, which is the corticoid apophysis. The humerus is still stouter in proportion than that of the Bakena, but the bones of the fore-arm are much more elongated. The fin is also much more pointed. There are only four well-marked fingers, which, not counting the metatarsals, have the following joints :—the index two, the middle and ring-finger seven each, and the little finger three : all the fingers are terminated by a cartilaginous dilatation.