The Cuviers divided the molar series of teeth, according to their form, into three kinds: "false mo lars," " carnassials," and "tubercu lar molars ; " and, in giving the ge neric characters of Mammalia, based the dental formulae on this system : thus the genus Fels is characterised as having " fausses molaires 2-2 1— earnassieres 1 tuberculeuses —s = 6 The uninterrupted line marked " Cuvier" in V. FELIS of fig. 580., intersects the teeth in each jaw called carnassieres ; those anterior to them being the teeth called " fausses molaires ;" the single tooth behind in the upper jaw is the " tu berculeuse." Most Zoologists, both at home and abroad, have adopted the Cuvierian system of formalising the molar teeth. It seems a very natural one in the case of the Cat = "Les Dents des Mammiferes consi d6r‘es comme Caracteres zoologiques," 8vo. p. 77. In the original the numbers 2 are given E 4 2 m. C. 6 t. , the teeth of each side being clubbed together ; they are distinguished into right and left in the text, to facilitate the comparison with the formulae used in this Article.
genus ; the tooth p. 4 above plays upon that, m. 1, below, which has a similar remarkable carnassial modification of form ; they fit, in deed, almost as Cuvier describes, like the blades of a pair of scissors ; the two teeth in advance of the carnassial in the upper jaw (p. 3, p. 2) in like manner are opposed to the same number of " fausses molaires " (p. 4, p. 3) in the under jaw, and the canine c. above plays upon the canine below ; all seems straightforward and symmetrical, save that the little tubercular, m. 1, above has no op ponent in the lower jaw. And, perhaps, the close observer might notice that, whilst the upper canine, c., glides behind its homotype be low, the first upper false molar (p. 2) passes anterior to the crown of the first false molar (p. 3) below ; and that the second false molar and carnassial of the upper jaw are also a little in advance of those teeth in the under jaw when the mouth is shut.
In passing to the dentition of the Dog (fig. 580, III. CANts), formulised by Cuvier as: 1-1 "fausses molaires 3--3 carnassieres —1-1' tu 2-2 ' 12 berculeuses — • = „ it will be ob 2-2 served that here the first upper false molar (p. 1) differs from that in Felis, inasmuch as, when the mouth is shut, it preserves the same relative position to its opponent below (p. 1) which the upper canine does to the lower canine, and that the same may be said of the second and the third false molars ; but that with regard to the carnassial above (p. 4) this tooth repeats the same relative position in regard to the fourth false molar below (p. 4), and not to that tooth, ni. 1, which Cuvier regarded as the lower homotype of the carnassial ; and, indeed, the more back ward position of the lower carnassial is so slight that its significance might well be over looked, more especially as the two succeed ing tubercular teeth above were opposed to two similar tuberculars below. Cuvier there
fore leaves us to conclude that the tooth which had no homotype or answerable op ponent aboie was either the fourth " fausse molaire " below, or else the first. How un important size and shape are, and how sig nificant relative position is in the determina tion of the homologies of teeth as of other parts, may be learnt before quitting the na tural order of Carnivora ; e. g. by the condi tion of the dental system in the Bear (fig. 580, II. Ustsus). Here the lower tooth, m. 1, instead of presenting the carnassial character, and resembling in form the upper tooth (p. 4), which is the homologue of the upper car nassial in the dog, has a tubercular crown, and corresponds in size as well as shape with the upper tooth 7n. 1, to which it is almost wholly opposed, and with the same slight advance of position which we observe in the lower canine as compared with the upper one, and in the four lower premolars (p. 1, p. 2, p. 3, p.4) as com pared with their veritable homotypes above. F. Cuvier divides the molar series of the 3-3 genus Ursus into " fitusses molaires — ., 1.-1 2-2 12 carnassicres tuberculeuses = The tendency in every thinker to generalise and to recognise Nature's harmonies, has led him here to use the term " carnassiere " in an arbitrary sense, and to apply it to a tooth above (p. 4), which he owns has such a shape and diminished size as would have led him to regard it as merely a false molar, but that the upper carnassial would then have entirely dis appeared ; and it has also led him to give the name " carnassiere " to a tooth below, m. 1, which he, nevertheless, describes as having a tubercular and not a trenchant crown. In so natural a group as the true Carnivora it was impossible to overlook the homologues of the trenchant carnassials of the lion, even when they had become tubercular in the omnivo rous bear ; and Cuvier therefore, having de termined and defined the teeth so called in the feline genus, felt compelled to distinguish them by the same names after they had lost their specific formal character. And if, indeed, he had succeeded in discovering the teeth which were truly answerable or homotypal in the upper and lower jaws, the term " carnassial " might have been retained as an arbitrary one for such teeth, and have been applied to their homologues in Man, the Ruminant, or the Pachyderm, where they are as certainly de terminable as in those aberrant Carnivores, in which they have equally lost their sectorial shape. But the inconvenience of names in dicative of such specialties of form will be very obvious when the term comes to be applied to the three hindmost teeth in the Hycenodon (fig. 577.), which teeth answer to the broad crushing teeth, vi. 1, m. 2, and m. 3, in the bear and some other existing Car nivora. The analogous term "molar," having a less direct or descriptive meaning, is there fore so much the better as the requisite arbi trary name of a determinate species of teeth.