



, ,1 



err few hole. three or four, sometimes less. The rest of the inter- 

 nal contour of the nostrils belongs to the maifflaries. Their septum 

 U the vomer, which U united to the ethmoid bone u ordinarily. The 

 auxiliaries, after forming the long nmulv, and arriving in the neigh- 

 bourhood of the orbite, enlarge, and cover with a wide and dilated 

 band the coiling which the frontal bone gives to those cavities, and 

 the whole anterior mirface of the fronUl bone, with the exception of 

 the amall band, which they Buffer to appear along the occipital crest 

 They also touch the bone* of the note. The two uitenuaxillarie 

 form the external and anterior border of the nasal aperture, and 

 deceeod upon and between the two maxillaries up to the |x>iiit of the 

 inuzale, where they even chow themselves below ; but the nmxillaries 

 are seen a little between them, above, near the nostrils. 



lint the frontal bone does not entirely form the lower surface of the 

 ceiling of the orbit ; the anterior part is formed by a fiat and irregu- 

 lar bone, covered above, like the frontal, by the maxillary ; this, 

 which is the jugal bone, gives off from its anterior angle a slender and 

 long apophysis, which is directed backwards, and proceeds to articu- 

 late itself to the zygomatic apophysis of the temporal bone : this deli- 

 cate filament is the sole bony limit of the orbit below. The zygomatic 

 apophysis of the temporal bone unites itself to the postorbital apo- 

 physU of the frontal, in order to limit the orbit backwards ; whence it 

 happens that the whole zygomatic arch properly so called appertains 

 to the temporal bone, which last extends but little into the temple, 

 and terminates at the temporal crest, so that it does not appear in the 

 occiput. Below, the lateral occipital and the basilary bones produce 

 projecting plates, which, uniting to the continuation of the ptery- 

 goidean ala and to a lamina of the temporal bone, compose a sort of 

 vault, under which are suspended by ligaments the petrous and tym- 

 panic bones, which are promptly conjoined into one piece. The 

 parietal bone, after having passed behind the temporal, forms a part 

 of this vault. The temporal bone itself therefore seems to be almost 

 foreign to the composition of the cranium, only serving to stop some 

 mall holes remaining in the parietal. This, Cuvier observes, is the 

 commencement of the separation which it undergoes in the inferior 

 nlinncin The part of these crests which borders the basilary region 

 on each side makes this region resemble a wide canal. At the bottom 

 of the orbit are seen the two sphenoids placed as ordinarily the 

 posterior touching the temporal, the parietal, and the frontal ; the 

 anterior touching the posterior, the frontal, and the internal pterygoid 

 apophysis : but the great peculiarity is the form of the bock nostril*. 

 The maxillaries being prolonged into a flattened muzzle, and the teeth 

 terminating in front of the orbit, the maxillary is not on the floor nor 

 on the anterior or lateral walls of that cavity, but at its ceiling, as is 

 also the jugal bone : it completes the internal border of this ceiling. 

 From the entire posterior contour of the lower surface or palatine of 

 these maxillary bones rises a sort of quadrangular pyramid, whose 

 base is traversed vertically by the nostrils, and in which the rest of 

 the space is hollow, or contained between two laminae open behind. 

 These form a sort of double walls, which surround the posterior aper- 

 ture of the nostrils. They are composed of the palatines and the 

 pterygoid internal apophyses. Each palatine is folded back on itself 

 in an irregular ring to form the base of this double wall, and the 

 ceiling is completed by the maxillary to which it U articulated. The 

 internal pterygoid apophyaft is only recurved in the form of S. One 

 of its curvatures articulates itself externally to the palatine to prolong 

 the lower and external wall ; the other unites to the other arch of 

 the palatine, and afterwards continues on the anterior sphenoid to 

 articulate itself to the vomer, and thus complete the internal part of 

 this entourage of the back nostril ; whence it results, that the entire 

 border of the back nostril, except the vomer, belongs, an in the Aut- 

 Eaters, to the internal pterygoid apophysis. The great sinus inter- 

 cepted between the two walls of this border is a peculiarity in the 

 Dolphin : this internal pterygoid always remains distinct. The poste- 

 rior sphenoid is conjoined with the basilary much sooner than to the 

 anterior sphenoid : Cuvier even found it conjoined in some foetuses 

 before any of the other bones. This nearly absolute derangement of 

 the bone* has, Cuvier observes, much changed the direction of the 

 holes. In place of the incisive hole there is a long canal, which pro- 

 ceed* between the two maxillaries and the two intermaxillaries, from 

 the end of the muzzle to the nostrils, near which it bifurcates. The 

 uborbiUl hole is to be sought in the ceiling of the orbit, where it 

 represent* a cavity open below, from which proceed in different direc- 

 tions canal* which go to open on the superior surface of the maxillaries 

 and intennaxillarie*, not below but above and opposite to the orbit 

 Cuvier could find neither lachrymal bone nor hole. In a hollow in 

 front of the orbit, between the maxillary, the vomer, and a point ol 

 the palatine bone, i* a moll hole which ascends in the nostril and 

 represent* the spheno-palatlne. To respond to the pterygo-palatine, 

 Cuvier could only perceive a small hole on the junction of the palatine 

 to the maxillary in the palate, which enters the sinus placed on each 

 side of the posterior nostril*. The optic hole is moderate and in the 

 anterior sphenoid u ordinarily. The aphcno-orbital hole between the 

 two sphenoid* also performs the office of the round hole. There i* an 

 oral hole in the posterior sphenoid, and more Internally in the same 

 bone a hole for a vessel. An aperture between the temporal, the 

 lateral occipital, the basilary, and the posterior sphenoid gives passage 

 to the nerve* of the ear to go to the petrous bone. In front of it, and 



very near, is the carotidean hole. In the basilary bone, and in a notch 

 >f the borders of this vault of the ear, is the oondyloidoan In !. wlii.-h 



very small. It is the posterior border of this vault which occupies 

 ;he place of the mastoid apophysis. 



Internally the cerebral cavity is very remarkable, inasmuch as its 

 leight surpasses its length. The floor is very compact The sclla is 

 >ut slightly marked. The cerebellar fossa are the most hollowed ; 

 there is often a very projecting bony tentorium in its middle ; tlir 

 fall is always bony backwards, but it ha* no crest, and some Mn.-ill 

 ioles are scarcely perceptible in the cribriform plate. The p- 

 and tympanic bones are not joined to the cranium by any suture, and 

 are not even inclosed, but only suspended by ligaments under the sort 

 of vault above noticed. They unite at an early j.-ii,..l into u single 

 bone of the ear. The occipital condyles are large, but project little. 

 The hole, directed entirely in the line of the head, is nearly circular. 



Cuvier remarks that complete symmetry is never found in the skulls 

 of Dolphins ; the two nostrils, the two nasal bones, and the a.! 

 parts, never appeared to him equal, as in other mammiferous animal - ; 

 md this, he observes, conducts us to the extreme inequality of those 

 parts in the Cachalots. 



The various species of Dolphins differ front each other in the relative 

 length and width of the muzzle, the number of teeth, and the 

 convexities or concavities of their parts, the palate, &c. Cuvier point* 

 out these variations in the species, and particularly notice* the Dolphin 

 of the Ganges (Susuk) as the most extraordinary in the struct .u . of 

 its cranium. 



Skull of Porpcsso. 



In the common Dolphin the seven cervical vertebras are united in r\ 

 single body, and so they are in the Porpesse; but this is not univer- 

 sally the cose, for in the Dolphin of the Ganges, for instance, the 

 cervical vertebra) are as distinct as in any quadruped. But where 

 they are ouchylosed, as in the common Dolphin, the atlas is fully 

 developed, and has sufficiently strong, transverse, conic apophy~< -. 

 The body of the axis is very delicate; but its spinous apophysis, 

 anchylosed to the atlas, is also well marked. The four suce. 

 vertebra) arc, to use Cuvicr's expression, as thin as paper, and their 

 annular part unites above to the lower surface of the spine of the axis. 

 The seventh cervical has some volume and rather strong distinct 

 apophyses. The dorsal vertebra) ore 13 in number, and there are 

 13 ribs. The first three ribs only have a head and a tubercle, and 

 are articulated on the body of two vertebras and on the extremity 

 of the transverse apophysis of one of them. The ten succeeding ribs 

 are only articulated to the extremity of the transverse apophysis. 

 The lost cervical and the first six dorsal have their articular apophyses 

 united to each other by horizontal surfaces, the anterior of which is 

 above. At the sixth they begin to become oblique ; at the seventh 

 they are nearly vertical. Commencing with the fourth, the transverse 

 apophysis gives off a small point from its anterior border. This point 

 approaches the anterior articular apophysis, and becomes blended with 

 it at the seventh ; afterwards these points form the only articular 

 apophysis; those of one vertebra embracing the lower part of Hie 

 spinous apophysis of the preceding vertebra. Towards the twenty. 

 second vertebra or the second lumbar they no longer reach it ; but 

 they remain irregularly marked for upon the tail. The transverse 

 apophyses of the lumbar region are very long, and the spinous very 

 high. On the tail they arc shortened ; the spinous ore widened ; :md 

 the transverse are directed rather forwards. They disappear at the 

 forty-ninth vertebra, and the spiuous at the fifty-first or fifty-second. 

 The V-shaped bones (hicmapopnyses of Professor Owen) of the uiu lei- 

 part of the tail commence under the thirty-eighth. The l>o,ly of the 

 vertebra) are round, rather angular below ; more compressed and 

 thicker in the region of the back ; shorter in the lumbar region and 

 in that of the tail, where they present a kind of carination I.. !. 

 The anterior and posterior opipnyses remain a long time distiuet. 

 The sternum is composed of three bones; the first. \>T\ \\ide, is 

 notched in front, and gives off on each side between the fn 

 second rib a sharp point directed backwards. There is a hole in the 

 middle. The second is simply rectangular. Between the first and 

 it the second rib is articulated ; the third rib is attached betwe 

 second and third bone, which receives on its sides the fourth, :md 

 towards its point the fifth and sixth, which is the last true rib. The 

 sternal parts of the ribs are all ossified. 



The shoulder-blade is fan-shaped, with the external surface slightly 

 concave, and it* spinal border forming the segment of a circle : the 



