In the left anterior occipito iliac position, or that when the back of the child's head is against the left side of the mother's pelvis, and nearest the pubes, while its forehead is against the right side, and nearest the sacrum,--the sagittal suture, or opening along the top, will of course run across from right to left. This opening may be distinctly felt with the finger, which should be passed along it towards the right side, and it will then reach the _anterior fontanelle_; afterwards it should also be passed to the left side, and then it will reach the _posterior fontanelle_. The difference between these two openings, in shape and size, is shown in Plate XXIV, and even if a person has never seen, or felt, the head of a newborn child, they can scarcely be taken for each other, after noticing that Plate. If the anterior fontanelle should be felt on the left side instead of the right, and near the pubes, while the posterior fontanelles is to the right, and near the sacrum, the position must be the _right posterior occipito iliac_, or just the reverse of the former. If the sagittal suture should be found to run across from the pubes to the sacrum, instead of from one side to the other, it will then indicate either an occipito pubic, or occipito sacral position, according as the back of the head is behind or before; and this can be readily ascertained by finding either of the fontanelles. In short, if the relative position, forms, and directions of these openings in the child's head be clearly understood, the position of the head can nearly always be determined by feeling them, as will be evident by referring to our former explanation of them. Sometimes however, the bones overlap a good deal, from the head being pressed, and then instead of an opening along the top, a _seam_ will be felt. And sometimes, from long continued pressure, a quantity of blood, and watery fluid, will be effused under the scalp, so as to prevent the bone being distinctly touched. But these accidents seldom happen, and with ordinary care and perseverance, need not prevent the position being determined, after a little delay. The position of other presenting parts is easily ascertained, by feeling for some known point--as the _nose_, or the face, the depression between the cheeks, or the breech, and so on.