The shape of the palate in a child of two years does not differ so markedly as one would at first expect from that of an adult except in length, and the reason for this is plainly the existence in the latter of three additional teeth on each side. Its increase in length is from 20 to 30 millimetres, whilst its breadth is only augmented by 10 to 15 mm., and this mainly posteriorly. When once the permanent incisors, canines, and premolars are developed, the anterior portion of the palate alters but little in shape, unless any of these teeth be lost, and the gaps not artificially maintained. Dr. Ehrmann[36] states that the alveolar border in front of the canine teeth forms a nearly regular semicircle, with a posterior transverse diameter of 22-26 mm.; thence the alveoli diverge regularly, adding to the diameter about 2-4 mm. for each tooth. He gives the following measurements as the mean of many observations: |From 2-6 yrs.|From 7-10 yrs.|From 11 yrs. ------------------------------+-------------+--------------+------------ Interval between canines |22-25 mm. |23-27 mm. |25-28 mm. ------------------------------+-------------+--------------+------------ ” 1st premolars|24-29 ” |25-30 ” |27-30 ” ------------------------------+-------------+--------------+------------ ” 2nd ” |26-31 ” |28-32 ” |31-34 ” ------------------------------+-------------+--------------+------------ ” 1st molars |— |— |32-37 ” Oakley Coles[37] has carefully investigated the size of the palate in several series of skulls in the Museum of the College of Surgeons, and gives the results as follows: Of 34 adult skulls of European origin, the average length was 49 mm., the average width at the second bicuspid was 35 mm., and the average height from the margins of the alveoli 9 mm. Of 32 adult skulls of mixed races, the average length was 54 mm., the width 35 mm., and the height 12 mm.