[218] A fossil grinder in the collection of John Macgowan, Esq. of Edinburgh, answers nearly to Mr Collinson's description, and is very well represented by the figure which accompanies it. This grinder weighs four pounds one-fourth avoirdupois; the circumference of the corona is eighteen inches; the coat of enamel is one-fourth of an inch thick; there are five double teeth; in Mr Collinson's specimen there are only four.
410. Though this argument appears to be of considerable weight, yet Camper, who was greatly skilled in comparative anatomy, and who had studied this subject with particular attention, was of opinion, that these grinders belong to a species of elephant. This opinion he states in a letter to Pallas, who had found grinders and other bones of this same animal, on the western declivity of the Ural mountains.[219] Camper denies that the animal is carnivorous, because the incisores, or canine teeth, are wanting; and he argues farther, from the weight of the head, which may be inferred from the weight of the grinders, that the neck must have been short, and the animal must have been furnished with a proboscis. He afterwards abandoned the latter hypothesis, and gave it as his opinion that the incognitum was neither carnivorous, nor a species of the elephant.[220]
[219] Acta Acad. Petrop. tom. i. (1777,) pars posterior, p. 213, &c.
[220] Ibid. tom. ii. (1784,) p. 262.
411. Nevertheless, Cuvier, in a mémoire read before the National Institute of Paris, maintains, that the fossil bones of the new Continent, as well as most of those of the old, belong to certain species of the elephant; of which, at least, two do not now exist, and are only known from remains preserved in the ground. He distinguishes them thus:[221]
[221] Mémoires de l'Institut National, Sciences Physiques, tom. ii. p. 19, &c.
Elephas mammonteus,—maxillâ obtusiore, lamellis molarium tenuibus, rectis.
Elephas Americanus,—molarities multicuspidibus, lamellis post detritionem quadric-lobatis.
The latter species, which is meant to include the animal incognitum, is said to have lived, not only in America, but in many parts of the old Continent. Yet some late inquiries into the structure of the teeth of graminivorous animals, and particularly of the elephant, make it very improbable that the incognitum has belonged to this genus.[222] The grinders of the elephant have been found to consist of three substances, enamel, bone, and what is called the crusta petrosa, applied in layers, or folds contiguous to one another; and no vestige of this structure appears in the grinders of the unknown animal of the Ohio.[223] At the same time, Dr Hunter's assertion, that this animal was carnivorous, is rendered doubtful, not only by the want of canine teeth, but also from the resemblance between its grinders and those of the wild boar, which Mr Home has observed to be considerable.[224] The grinder of the boar is similar to that of the elephant, in the extent of the masticating surface, but not at all in the internal structure; and the same is true of the tooth of the animal incognitum, so that a considerable probability is established, that it and the boar are of the same genus, and both destined to live occasionally either on animal or vegetable food.
[222] See Mr Home's Observations on the Teeth of Graminivorous Animals, Phil. Trans. 1799. Also, an Essay on the Structure of the Teeth, by Dr Blake.