CETACEA. 



CTTACEA. 



extremity of this plane. The occipital crest comes near the base of 

 the nasal bones, traversing from one temporal crest to the other. On 

 the middle of this occipital surface is a slightly projecting longitu- 

 dinal ridge. 



The jugal bone is curved into a portion of a circle, and forms the 

 lower border of the orbit, coming from the zygomatic apophysis of 

 the maxillary bone, which abuts at the anterior angle on the temporal 

 apophysis, which abuts on the posterior angle. The jugal bone is not 

 dilated at its extremity as in the Dolphin. The frontal on one side 

 touches the maxillary, and on the other the temporal bones, by its 

 ante- and post-orbital apophyses, and forms by itself the whole ceiling 

 of the orbit, without being doubled above by the maxillary ; but on 

 the contrary it is below, on its anterior portion, that in front of the 

 orbit, and moreover is bordered there anteriorly by the lateral lamina 

 of the maxillary bone, which is, with reference to the frontal, in an 

 inverse position from that which it holds in the Dolphins. It is by 

 this lamina that the maxillary bone abuts on the anterior angle of the 

 orbit, and articulates itself with the anterior and enlarged extremity 

 of the jugal bone; but what is very remarkable is, that at this point, 

 'ii the frontal and the maxillary, and, so to speak, at their very 

 articulation, a peculiar bone, in form of a lamina, occupies nearly half 

 the length of that suture, and which perhaps is the analogue of the 

 lachrymal bone. The whole of the zygomatic arch, properly so 

 called, which is very large, belongs to the temporal bone. The frame 

 of the orbit is closed on all sides ; its ceiling is very large and concave 

 above. The palatine bones are prolonged below the keel of the 

 maxillarics. The posterior nostrils are very near the occipital hole. 

 They have at each angle a tuberosity formed by the pterygoidean 

 bone, which has little longitudinal extent, and only surrounds the 

 nustrils on the external side and a little above and below, but without 

 forming a sinus or double border there, as in the Dolphins. The 

 basilary region, which is very short, ig also hollowed into a canal, as in 

 them, and has on each side the bones of the ear, which are very small 

 in proportion, and of oval form, and equally convex in their inferior 

 surface. In front of the basilary bone, and between the pterygoidean 

 bones, may be seen the body of the posterior sphenoid. The glenoid 

 face of the temporal bone is nearly vertical, and looks forwards ; that 

 which makes the articular surface of the lower jaw is in some sort 

 the truncature of the extremity of the bone. This jaw is an arch 

 externally convex, compressed, slightly trenchant above and below. 

 It has a coronoid apophysis in form of an obtuse angle, and a tuber- 

 ojiity a little more backwards. 



Cuvier points out certain differences between the skulls of the 

 Rorqual* of the Cape, the Mediterranean, and the North Sea, for 

 which we must refer the reader to his ' Ossemens Fossiles." 



BaUena. To form the idea of a Balama, properly so called, Cuvier 

 states that we must figure to ourselves the muzzle of the Rorqual 

 narrowed, elongated, compressed laterally, and arched from before 

 backwards, nearly in a quarter of a circle. It is, he observes, in the 

 space which this curvature leaves, that the plates of baleen, or whale- 

 bone, which adhere by their upper and wide extremity to the sides 

 <if 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 Baltmuf, properly so called, that they are longer hi 

 those whales than in the Rorquals, in which last the nearly straight 

 muzzle leaves them little room. 



It results 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 last 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 Rorqual. 

 The occipital bone is convex throughout its upper portion, less 

 ul.>liqiic than in the Rorqual, and semi-oval. The temporal bone 

 in tiixnsvcrse, and its zygomatic portion hardly curves forwards 

 at all. The nasal bones are rhomboidal, and not triangular na in the 

 Rorqual. Below, the palatine and pterygoideau bones are thrown 

 still more back, and are shorter, and the sphenoid bone is more 

 concealed than in the Rorqual. The maxillary bone has a deep 

 nutuh at its lower and posterior border. The glenoid surface of the 

 temporal bone is much less vortical than in the Rorqual, so that the 

 lower jawbone rises a little to offer its articular convex surface. This 

 disposition, joined to the absence of a coronoid apophysis, may serve 

 to distinguish it from the lower jaw of the llorqiiul. 



In the Rorqual of the Cape, Cuvier found the atlas distinct from 

 the axis ; this hut is anchylosecl by the upper part of its ring, which 

 has no spinous apophy.-us, with the 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 

 in in the axis; one superior is given off from the annular 

 porti. in below the articular apophysis, the other from the lower part 

 of the body ; none of these apophyses are directed forwards. The 

 lower are Mhortrned from the axis to the fourth vertical and are 

 wanting in the succeeding ones. The upper apophyses ore longest on 

 the axis and on the third ; afterwards they are equal, and form a 

 series with the tr; - .physus which carry the ribs. There are 7 



cervical vertebra;, 14 dorsal vertebra) 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 vertebra;. 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 ou the first 

 dorsals. They form a nearly equal series ; wider on the middle of the 

 back, narrower, but always moderately elevated, on the lumbar region, 

 and shortening by degrees on the tail. They vanish on the last 

 twelve, and the annular portion disappears two vertebras 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 fourteeuth 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 vertebra) 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 iu their axis. 



The single bone of the sternum was square, deeply forked 

 posteriorly, and with a point at its external border. " 



The shoulder-blade of the Cape Rorqual is, Cuvier remarks, 

 entirely different from that of the Salcena ; it is wider than it is long, 

 semicircular on the spinal side, with a single anterior border, a single 

 prominence (the ocromion) towards the lower third, and a tubercle 

 near the articulation, which is the coracoid apophysis. The humerus 

 is still stouter in proportion than that of the Balcena, 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, aud the little finger three : all 

 the fingers are terminated by a cartilaginous dilatation. 



The bone of the ear in the Balaenm differs from that of the 

 Dolphins in the enormous thickness of the tympanic bone, especially 

 ou the internal side. The tympanic bonn is a little more closed iu 

 front, but leaves between it and the petrous bone on the internal side 

 a solution of continuity wider and longer in proportion. It is not 

 bilobated backwards. The petrous bone is of very irregular form, 

 and very rugged ; it gives off two great and stout apophyses, also 

 very rugged, one of which, posterior and a little superior, articulated 

 to a corresponding apophysis of the tympanic bone, is inserted 

 between the temporal and lateral occipital ; and the other, anterior 

 and inferior, is articulated by gquamous suture with the temporal 



Skull of Greenland Whale, with lower jaw, seen from above. 



Skull of Greenland Whule, seen from below. 



portion, which descends to furnish articulation with the lower jaw. 

 The ear-bones in all the Cetaceans are four in number, as in the 

 Mammalia, and the malleus is anchylosed to the frame of the tym- 

 panum, which, Cuvier observes, is the more singular, inasmuch as it 

 is not deprived of its muscles. 



