CETACEA. 



CETACEA. 



two other borders are slightly concave and nearly equal ; the anterior 

 is bifurcated, and thus presents two edges one external, the other 

 nearer the ribs. The external gives off a flat apophysis directed for- 

 wards, and enlarged at its extremity, which represents the acromion. 

 The other border, which is the true anterior border, gives off also, 

 but close to the articular surface, a flat apophysis, less than the 

 acromion, descending a little and equally enlarged at the end : this is 

 the coracoid process. The humerus is very short and stout. On the 

 anterior part of its upper extremity or head is a tuberosity as large 

 as itself: the lower head is enlarged and compressed from before 

 backwards, and does not terminate in a facet that may be termed 

 articular, but unites by synchondrosis with the radius and ulna : these 

 two bones are short and compressed. The radius is in front and the 

 largest, and its form is nearly rectangular : the ulna is behind and 

 narrower. Its posterior border is concave, and it forms at its upper 

 extremity a projecting angle, which is the only vestige of the olecranon. 

 The carpal bones are flat, angular, and together form a sort of pave- 

 ment. There are three in the first row, the anterior of which responds 

 to the radius," the posterior to the ulna, and the intermediate one to 

 both radius and ulna. In the second row there are four, the anterior 

 of which is the smallest. Under this anterior bone, which may be 

 also taken for a metacarpal, is a pointed bone which in the sole vestige 

 of a thumb. The next bone, which is the fore finger, is composed of 

 nine joints, which must represent its metacarpal, its phalanges, and 

 their epiphyses : there are seven in the third finger and four in the 

 fourth ; the fifth is reduced to a single very small tubercle. 



In the Narwhals the skull resembles that of the Dolphins, and 

 especially the head of the Beluga, in structure ; but instead of the 

 numerous teeth ranged along the maxillaries presented by the Dol- 

 phins generally, there is but one on each side, directed forwards and 

 implanted in an alveolus common to the maxillary and intermaxillary 

 bones. Very rarely indeed are these teeth symmetrical ; and nearly 

 always one of the two remains inclosed in its alveolus, whilst the 

 other grows to a length of ten or twelve feet. The muzzle, and more 

 especially the intermaxillary bones, are more widened than in the 

 Dolphins. The intermaxillaries ascend near to the bones of the nose. 

 The holes with which the maxillaries are pierced in their widened 

 part, and which occupy the place of the suborbital holes, are large 



Skull and Teeth of Narwhal (Miinmtw. mmu,rera}, seen from below. Owen. 



and numerous. The notch which separates this widened part from 

 the muzzle is small, and the upper part of the orbit projects but 

 little. The nasal are very small, and the left nostril is smaller than 

 the other. 



The number of vertebrao, according to Scoresby, are 7 cervical, 



SAT. HIST. i v. vol.. i. 



12 dorsal, and 35 lumbar or caudal 54 in all. The spinal canal 

 is said to cease at the forty-first. The spinous apophypes begin 

 to diminish at the thirty-fourth, and disappear at the thirty- 

 eighth. The V-shaped boues commence between the thirtieth and 

 the thirty-first, and terminate between the forty-second and forty- 

 third. There are six pairs of true ribs and six false, all rather slender. 

 The bones of the anterior extremity appear to bear a close resemblance 

 to those of the Porpcsse, except that the bones are more equal, as 

 might be expected from the roundness of the Narwhal's flipper. 



In the Hyperoodons the skull differs almost entirely in form from 

 those belonging to the Dolphins. From the maxillaries, which are 

 pointed in front and widened towards the base of the muzzle, rises ou 

 each of their lateral borders a large vertical crest, rounded above, 

 descending obliquely forwards and more rapidly backwards, where it 

 falls again nearly above the postorbital apophysis. Still more back- 

 wards, the maxillary bone, continuing to cover the frontal bone, 

 ascends vertically with it and with the occipital, to form on the back 

 part of the head a transverse occipital crest, which is very elevated 

 and very thick, so that on the skull of the animal there are three of 

 these great crests : the occipital crest behind, and the two maxillary 

 crests on the sides, which are separated from the first by a wide and 

 deep notch. They do not approximate above, nor do they form a 

 vault, as in the Dolphin of the Ganges, but simply a sort of lateral 

 walls. The intermaxillaries, placed as ordinarily between the maxil- 

 laries, ascend with them to the nostrils, and passing by the side of 

 them, raise themselves above, so that they take part in the formation 

 of the posterior crest elevated upon the occiput. The two nasal bones, 

 which, as well as the nostrils, are very unequal, are placed at the 

 anterior surface, of this occipital crest, and are raised to its summit. 

 In other respects the connections of the bones are nearly the same as 

 in the Dolphins. 



The zygomatic apophysis of the temporal bone is thick, without 

 being as long as in the Dolphin of the Ganges ; the orbit is as wide 

 as in the ordinary Dolphins, and bounded in like manner below by a 

 slender stem given off by the jugal bone. Tlu' park-tal bones show 

 themselves but very little in the temporal fossa, which is itself not 

 much extended in height Below, the palate is slightly carinated, 

 indicating an approximation to the lialrrna. The lateral furrows 

 observable in the common Dolphin are absent. The pterygoideans 

 occupy a very great length in the back-nostrils, and much diminish 

 the portion which the palatine bones fill in front. The vomer shows 

 itself at two points of the lower surface, between the pterygoideans 

 and the palatines, and between the maxillaries and intermaxillaries. 

 The occiput is higher than it is wide. The lower jaw has not the 

 symphysis longer than in the ordinary species of the Dolphins. 



Tho seven cervical vertebra; are all anchylosed together ; there are 

 thirty-eight other vertebra;, nine of which carry the ribs. At the 

 twenty-second the V-shaped bones which characterise the first caudal 

 commence, so that seventeen caudal vetebroe may be counted. There 

 are six of these V-shaped bones ; and the superior spinous apophyses 

 cease on the ninth caudal. The five first ribs only are articulated to 

 the sternum, and there are only four false ribs on each side. The 

 sternum is composed of three bones, the first square, notched in front 

 and behind ; the second square also, and notched in front ; the third 

 oblong and notched behind. 



The shoulder-blade has the spinal border more extended in pro- 

 portion and more rectilinear than in the Dolphins, the anterior angle 

 more pointed, the acromion directed rather downwards, and the cora- 

 coid process a little in the opposite direction. The bones of the arm 

 and fore-arm are a little less shortened than in the Dolphins. ('Ossemens 

 Fossiles.') 



The skull of the Cachalots bears a nearer resemblance to that of 

 the Dolphins than to that of any other Cetaceans. The immense 

 muzzle, notwithstanding its prodigious extent, is, like that of the 

 Dolphin, formed by the maxillaries on the sides, the intermaxillaries 

 towards the mesial line, and the vomer on that line. The inter- 

 maxillaries reach beyond the other bones to form the anterior point : 

 they ascend on the two sides of the nostrils and the nasal bones, and 

 raise themselves to form that species of wall which elevates itself 

 perpendicularly and circularly on the back of the head, but that of 

 the right side is carried higher than that of the left. The vomer shows 

 itself between them in considerable width, especially at the upper 

 part ; it is hollowed into a semicanal throughout its length. The 

 nostrils are pierced at the foot of this sort of wall at the root of the 

 vomer, and between the raised and ascending parts of the two inter- 

 maxillaries. Their direction is oblique from below upwards, and 

 from behind forwards. They are excessively unequal, and that on 

 the right side is not a fourth of the size of that on the left. The 

 nasal bones are also very unequal. Both ascend between the intermaxil- 

 laries against the foot of the semicircular wall which is raised upon 

 the cranium, but they only rise to the level of the left intermaxillary. 

 The right nasal bone is not only larger than the other, but it also 

 descends lower between the two nostrils, articulating itself upon the 

 root of the vomer, and giving to that part an irregular crest which 

 reposes a little obliquely on the left -nostril, which, as before olwrvrd, 

 is the longest. 



The direction of the vomer and amplitude of the left nostril 

 indicate a direction of the membranous canal of the nostrils and the 



3 1 



