How to use Incisor in a sentence
The upper incisor teeth are generally marked by grooves.
The first upper incisor is much larger than the others; canine and first two premolars rudimentary.
In the more typical Lemuridae there are two pairs of upper incisor teeth, separated by a gap in the middle line; the premolars may be either two or three, but the molars, as in the lower jaw, are always three on each side.
Beavers are sociable animals, living in streams, where, so as to render the water of sufficient depth, they build dams of mud and of the stems and boughs of trees felled by their powerful incisor teeth.
The third incisor in both upper and lower jaws is large, developed before the others, with much the size, form and direction of the canine.Advertisement
The upper jaw is apparently destitute of incisor and canine teeth, but possesses five molars on each side, with a corresponding number in the jaw beneath.
The first in the upper jaw is strong, curved and cutting, the other two generally somewhat smaller; the single lower functional incisor large, more or less.
Lower incisors diminishing in size from the first to the third; the canine, which is in contact with the third incisor, large and conical, working against (and behind) the canine-like third upper incisor.
Between two and a half and three years the first incisor appears.
As a general rule, the depression caused by the infolding of the surface of the incisor (the " mark ") is obliterated in the first or central incisor at six years, in the second at seven years, and in the third at eight years.Advertisement
Rodents have permanently growing incisor teeth; they must continually gnaw to keep their teeth under control.
Here the metacarpals and metatarsals have partially united to form cannonbones, the skull has assumed the elongated form characteristic of modern camels, with the loss of the first and second pairs of upper incisors, and the development of gaps in front of and behind each of the next three teeth, that is to say, the third incisor, the canine and the first cheek-tooth.
He believed that the cast displayed ante mortem loss of the central and right lateral incisors, and possibly the left lateral incisor.
Finally, we have the family Rhinocerotidae, which includes the existing representatives of the group. In this family the dentition has undergone considerable reduction, and may be represented inclusive of all the variations, by the formula i a or a m a The first upper incisor, whenpresent, has an 430r2; PP antero-posteriorly elongated crown, but the second is small; when fully developed, the lower canine is a large forwardly directed tusk-like tooth with sharp cutting-edges, and biting against the first upper incisor.
In the latter there is only one pair of incisor teeth in the upper jaw, in which the enamel is confined to the front surface.Advertisement
In the rodents now to be considered, the angular process of the lower jaw arises from the outer side of the sheath of the incisor.
Pecora, or true ruminants as they may be conveniently called, have complex stomachs and chew the cud; they have no upper incisor teeth; and the lower canines are approximated to the outer incisors in such a manner that the three incisors and the one canine of the two sides collectively form a continuous semicircle of four pairs of nearly similar teeth.
In Protolabis of the Middle Miocene, while no cannon-bone is formed, the first and second pairs of incisor teeth are retained, and the limbs and feet are short and disproportionately small.
These three teeth, which are implanted in the premaxilla, form a distinct group, to which the name of " incisor " is applied.
The latter expand in front, and are curved downwards to form the semicircular alveolar border which supports the large incisor teeth.Advertisement
The palate is narrow in the interval between the incisor and molar teeth, in which are situated the large anterior palatine foramina.
The horizontal ramus, long, straight, and compressed, gradually narrows towards the symphysis, where it expands laterally to form with the ankylosed opposite ramus the wide, semicircular, shallow alveolar border for the incisor teeth.
At three years the second and third premolars, and the third molar have appeared, at from three and a half to four years the second incisor, at four to four and a half years the canine, and, finally, at five years, the third incisor, completing the permanent dentition.
Observations upon captive specimens have led to the conclusion that it feeds principally on juices, especially of the sugar-cane, which it obtains by tearing open the hard woody circumference of the stalk with its strong incisor teeth; but it is said also to devour certain species of wood-boring caterpillars, which it obtains by first cutting down with its teeth upon their burrows, and then picking them out of their retreat with the claw of its attenuated middle finger.
The duct which runs along its upper and internal border passes forwards in the usual course, lying in the inner side of the sublingual gland, to open on the outer surface of a distinct papilla, situated on the floor of the mouth, half an inch from the middle line, and midway between the lower incisor teeth and the attachment of the fraenum linguae.Advertisement
This order is named due to the modifications of the incisor teeth that project forward, in a similar way to rodents.
Canines-The two sharp teeth located next to the front incisor teeth in mammals that are used to grip and tear.
Between the ages of about six and 12 to 14, as the jaw grows, 28 permanent teeth erupt, replacing the primary teeth, incisor for incisor, canine for canine, premolar or bicuspid for molar.
The tusks, or upper incisor teeth, which were probably smaller in the female, in the adult males attained the length of from 9 to io ft.
The primitive Artiodactyla thus probably had the typical number (44) of incisor, canine and molar teeth, brachyodont molars, conical odontoid process, four distinct toes on each foot, with metacarpal, metatarsal and all the tarsal bones distinct, and no frontal appendages.
Brontops seem scarcely separated from the type genus; but the name Brontotherium is applied to species with two pairs of incisor teeth in both jaws.
In the upper jaw there is a compressed, sharp-pointed, tusk-like incisor near the hind edge of the premaxilla, followed in the male at least by a moderate-sized, pointed, curved canine in the anterior part of the maxilla.
The two points thus meeting, the bill is 1 This peculiarity is found as an accidental malformation in the crows (Corvidae) and other groups; it is comparable to the monstrosities seen in rabbits and other members of the order Glires, in which the incisor teeth grow to an inordinate length.
The three incisors of the upper jaw are arranged in a continuous arched series, and have crowns with broad cutting edges; the first or middle incisor is often larger than the others.
In the rat-kangaroos, or kangaroo-rats, as they are called in Australia, constituting the sub-family Potoroinae, the first upper incisor is narrow, curved, and much exceeds the others in length; the upper canines are persistent, flattened, blunt and slightly curved, and the first two premolars of both jaws have large, simple, compressed crowns, with a nearly straight or slightly concave free cutting-edge, and both outer and inner surfaces usually marked by a series of parallel, vertical grooves and ridges.
As a sub-order, the Paucituberculata are characterized by the presence of four pairs of upper and three of lower incisor teeth; the enlargement and forward inclination of the first pair of lower incisors, and the presence of four or five sharp cusps on the cheek-teeth, coupled with the absence of "syndactylism" in the hind limbs.
It may be added that a few traces of mammals have been obtained from the English Wealden, among which an incisor tooth foreshadows the rodent type.
Teeth variable in number, owing to the suppression in some forms of an upper incisor and one or more premolars.
This animal, whose remains occur in the Lower Pliocene of both Attica and Samos, was about the size of a donkey, and possessed three pairs of upper incisor teeth, of which the innermost were large and trihedral, recalling those of the existing genus.
The basal line of the cranium from the lower border of the foramen magnum to the incisor border of the palate is nearly straight.
The first teeth which appear are the first and second milk-molars (about five days), then the central incisor (from seven to ten days); this is followed by the second incisor (at one month), then the third molar, and finally the third incisor.
There are but three pairs of incisor teeth in each jaw, and the upper molars are tricuspid.
In this group the incisors and canines are very variable in number and form; the lower canine being separated by only a short gap from the outer incisor (when present), but by a long one from the first premolar, which is in contact with the second.