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Show 210 MAMMALIA. MoNo:tioN, Lin. The Narwhals have no teeth properly. speak~ng, but .mere long, straight and pointed tusks, im~lanted m the mtermaxlllary bon~, and directed in the line of the axts of the body. The form of thetr body and that of their head greatly resemble that of the Porpoises. One species only is well known, the M. monoceros, L.; Scoresby, Arct. Reg. pl. xv.(l) TheNarwhal.) The tusk of this animal, which is spirall_y furrowed and sometimes ten feet in length, was for a lotlg t1me ca1Ied the horn of the Unicorn. It has, it is true, the germs of two tusks, but it is very seldom that both become equally developed. That of the left side usually attains its full growth, while the other always remains hidden in its alveolus.(2) AccorditJg to the description of the Narwhal, it is hardly more than twice or thrice the length of its tusk; the skin is marbled with brown and a kind of white; the muzzle is arched; mouth sma11; spira· cle on top of the head, and no dorsal fin, but merely a salient crest along the spine. The tusks are sometimes found perfectly smooth.(3) The other Cetacea have the head so large as to constitute one third or one half of the length of the whole body; but neither the cranium nor the brain participate in this dispro· belongs to the Grampus, is the same as the Two-toothed Dolphin of Hunter; Baus· sard expressly mentions its two teeth. lt is also the Balama rostrata of Klein and of Chemnitz, Besch. der Berl. ges. IV, P· 183; of Pennant, llrit. Zool. No. V; of Pontoppidan, Nar. II, 120; the Bottle-head of Dale, &c. Chemnitz found one of the teeth. See Oss. Foss. tom. V, p. 1, f. 324. (1) The Narval microcephale, Lacep. pl. v, f. 2, is nothing more than a common Narwhal, not quite so badly figured as in pl. iv, f. 3, which is copied from & bad drawing of Klein, Pisc. per Pulm. Resp. pl. ii, fig. c, from an individual capt~red in the Elbe in 1736, afterwards stuffed and exhibited in Dresden. Anderson gtves a rather better figure of the same individual. Fr. Tr. JI, p. 108. (2) We have found this small tusk in several crania, and verified the statements of Anderson on this subject. It is prevented from being developed by its intern~ cavity becoming too rapidly filled with the mattel' of the iv01·y, which thus obliter· ates its gelatinous core. · (3) The Monodon apurius of Fabricius, or .!lna1•kak of Greenl:l.nd, (Jlncy/odon, Illig.) which has but two small curved teeth in the upper jaw and n dorsal fin, cannot be far removed from the Hyperoodon. Val, wale, in all the languages ~e· rived from the Teutonic, signifies Whale, and is often employed for the Cetacea 111 general; nar, in the language of the 'Idelanders, means cadaver, or dead body, and it is pretended that such is the food of this genus. CETACEA. 211 portion, which is altogether owing to an enormous development of the bones of the face. PHYSETER_, Lin. The Cachalots(!) are Cetacea with a very voluminous head, excessively enlarged, particularly in front, in whose upper jaw there is neither wh~lebone nor tooth, Ol' if any, very small, and not projecting; the lower Jaw, narrow, elongated, and corresponding to a furrow in the upper one, is armed on each side with a range of cylindrical or conical teeth, which, when the mouth is closed, enter into corresponding cavities in the upper jaw. The superior portion of their enormous head consists almost entirely of large cavities, separated and covered by cartilages, and filled with an oil which becomes fixed as it cools, well known in commerce by the name of spermaceti a s~bstance for which they are principally sought; the body no; havmg much fat, and consequently yielding but little oil. These cavities, however, are very distinct from the true cranium which is rather small, is placed under their posterio1· portion and :ontains the brain as usual. It appears that canals, filled with' this spermaceti, or adipocire as it is called, are distributed to several parts of the body, communicating with the cavities which fill the mass of the head; they even ramify through the fat or blubber that is found beneath the skin. T~e odorous substance, named ambergris, appears to be a concrett~ n formed in the intestines of the Cachalot, particularly during certam states of disease, aud it is said, chiefly in the c~cum. The species of the Cachalots are far from being well ascertained. That which appears to be the most common, the macrocephalus of Shaw and Bonnaterre, (Lacep. X)(2) in lieu of a dorsal fin, has a mere callous prominence. There are from twenty to twenty-three teeth on each side of the lower jaw, and some small conical ones hidden beneath the gum in the upper one. Its spiracle is single, and not double as in the greater part of the other Cetacea; neither is it symmetrical, but is directed towards the left, and terminates on that side, on the front of.tbe muzzle, which is truncated.(3) In addition to this, it is satd that the left eye is much smaiier than the other, and that th (l). Phyaeter as well as pltysalus, signifies blower. Cachalot is the name used by ~2~Jsca~ans ; from cachau, which in the Cantabrian dialect means tooth. It 18 not the macrocephalus of Linnll:us. (S) We have verified on two crania this want of symmetry in the spiracle, announced b D dl th . Y u ey, by Anderson and by Swediauer, which inclines us to credit e Inequality of the eyes mentioned by Egede. . |
